diff --git a/inc/MicroBit.h b/inc/MicroBit.h
index 53bff1c..184a3a0 100644
--- a/inc/MicroBit.h
+++ b/inc/MicroBit.h
@@ -3,7 +3,7 @@
 
 #include "mbed.h"
 
-#include "MicroBitConfig.h"  
+#include "MicroBitConfig.h"
 #include "MicroBitHeapAllocator.h"
 #include "MicroBitPanic.h"
 #include "ErrorNo.h"
@@ -12,7 +12,7 @@
 #include "MicroBitComponent.h"
 #include "ManagedType.h"
 #include "ManagedString.h"
-#include "MicroBitImage.h"	
+#include "MicroBitImage.h"
 #include "MicroBitFont.h"
 #include "MicroBitEvent.h"
 #include "DynamicPwm.h"
@@ -59,16 +59,16 @@
   * Represents the device as a whole, and includes member variables to that reflect the components of the system.
   */
 class MicroBit
-{                                  
+{
     private:
-    
+
     void                    seedRandom();
     void                    compassCalibrator(MicroBitEvent e);
     uint32_t                randomValue;
 
-  
+
     public:
-    
+
     // Map of device state.
     uint32_t                flags;
 
@@ -76,43 +76,43 @@ class MicroBit
     Ticker                  systemTicker;
 
     // I2C Interface
-    MicroBitI2C             i2c;  
-    
+    MicroBitI2C             i2c;
+
     // Serial Interface
-    MicroBitSerial          serial;   
+    MicroBitSerial          serial;
 
     // Array of components which are iterated during a system tick
     MicroBitComponent*      systemTickComponents[MICROBIT_SYSTEM_COMPONENTS];
-    
+
     // Array of components which are iterated during idle thread execution, isIdleCallbackNeeded is polled during a systemTick.
     MicroBitComponent*      idleThreadComponents[MICROBIT_IDLE_COMPONENTS];
 
     // Device level Message Bus abstraction
-    MicroBitMessageBus      MessageBus;     
-    
+    MicroBitMessageBus      MessageBus;
+
     // Member variables to represent each of the core components on the device.
     MicroBitDisplay         display;
     MicroBitButton          buttonA;
     MicroBitButton          buttonB;
-    MicroBitMultiButton     buttonAB;    
+    MicroBitMultiButton     buttonAB;
     MicroBitAccelerometer   accelerometer;
     MicroBitCompass         compass;
     MicroBitThermometer     thermometer;
 
     //An object of available IO pins on the device
     MicroBitIO              io;
-    
+
     // Bluetooth related member variables.
 	MicroBitBLEManager		bleManager;
     BLEDevice               *ble;
-    
+
     /**
-      * Constructor. 
+      * Constructor.
       * Create a representation of a MicroBit device as a global singleton.
       * @param messageBus callback function to receive MicroBitMessageBus events.
       *
       * Exposed objects:
-      * @code 
+      * @code
       * uBit.systemTicker; //the Ticker callback that performs routines like updating the display.
       * uBit.MessageBus; //The message bus where events are fired.
       * uBit.display; //The display object for the LED matrix.
@@ -124,16 +124,16 @@ class MicroBit
       * uBit.io.P*; //Where P* is P0 to P16, P19 & P20 on the edge connector
       * @endcode
       */
-    MicroBit();  
+    MicroBit();
 
     /**
       * Post constructor initialisation method.
-      * After *MUCH* pain, it's noted that the BLE stack can't be brought up in a 
+      * After *MUCH* pain, it's noted that the BLE stack can't be brought up in a
       * static context, so we bring it up here rather than in the constructor.
       * n.b. This method *must* be called in main() or later, not before.
       *
       * Example:
-      * @code 
+      * @code
       * uBit.init();
       * @endcode
       */
@@ -157,7 +157,7 @@ class MicroBit
       * Will reset the micro:bit when called.
       *
       * Example:
-      * @code 
+      * @code
       * uBit.reset();
       * @endcode
       */
@@ -168,15 +168,15 @@ class MicroBit
       * If the scheduler is running, this will deschedule the current fiber and perform
       * a power efficent, concurrent sleep operation.
       * If the scheduler is disabled or we're running in an interrupt context, this
-      * will revert to a busy wait. 
-      * 
+      * will revert to a busy wait.
+      *
       * @note Values of 6 and below tend to lose resolution - do you really need to sleep for this short amount of time?
       *
       * @param milliseconds the amount of time, in ms, to wait for. This number cannot be negative.
-      * @return MICROBIT_OK on success, MICROBIT_INVALID_PARAMETER milliseconds is less than zero. 
+      * @return MICROBIT_OK on success, MICROBIT_INVALID_PARAMETER milliseconds is less than zero.
       *
       * Example:
-      * @code 
+      * @code
       * uBit.sleep(20); //sleep for 20ms
       * @endcode
       */
@@ -191,7 +191,7 @@ class MicroBit
       * @return A random, natural number between 0 and the max-1. Or MICROBIT_INVALID_PARAMETER if max is <= 0.
       *
       * Example:
-      * @code 
+      * @code
       * uBit.random(200); //a number between 0 and 199
       * @endcode
       */
@@ -202,27 +202,27 @@ class MicroBit
       * provide a power efficient sense of time.
       */
     void systemTick();
-    
+
     /**
       * System tasks to be executed by the idle thread when the Micro:Bit isn't busy or when data needs to be read.
       */
     void systemTasks();
 
     /**
-      * add a component to the array of system components which invocate the systemTick member function during a systemTick 
+      * add a component to the array of system components which invocate the systemTick member function during a systemTick
       *
       * @param component The component to add.
       * @return MICROBIT_OK on success. MICROBIT_NO_RESOURCES is returned if further components cannot be supported.
       */
     int addSystemComponent(MicroBitComponent *component);
-    
+
     /**
       * remove a component from the array of system components
       * @param component The component to remove.
       * @return MICROBIT_OK on success. MICROBIT_INVALID_PARAMETER is returned if the given component has not been previous added.
       */
     int removeSystemComponent(MicroBitComponent *component);
-    
+
     /**
       * add a component to the array of of idle thread components.
       * isIdleCallbackNeeded is polled during a systemTick to determine if the idle thread should jump to the front of the queue
@@ -230,7 +230,7 @@ class MicroBit
       * @return MICROBIT_OK on success. MICROBIT_NO_RESOURCES is returned if further components cannot be supported.
       */
     int addIdleComponent(MicroBitComponent *component);
-    
+
     /**
       * remove a component from the array of idle thread components
       * @param component The component to remove.
@@ -245,7 +245,7 @@ class MicroBit
       * TODO: handle overflow case.
       */
     unsigned long systemTime();
-    
+
     /**
       * Determine the version of the micro:bit runtime currently in use.
       *
@@ -256,7 +256,7 @@ class MicroBit
 
     /**
       * Triggers a microbit panic where an infinite loop will occur swapping between the panicFace and statusCode if provided.
-      * 
+      *
       * @param statusCode the status code of the associated error. Status codes must be in the range 0-255.
       */
     void panic(int statusCode = 0);
@@ -274,4 +274,3 @@ extern "C" void app_main();
 
 
 #endif
-
diff --git a/inc/MicroBitAccelerometer.h b/inc/MicroBitAccelerometer.h
index 1a26398..6d7b00b 100644
--- a/inc/MicroBitAccelerometer.h
+++ b/inc/MicroBitAccelerometer.h
@@ -57,7 +57,7 @@
 #define MICROBIT_ACCELEROMETER_EVT_FACE_UP                  5
 #define MICROBIT_ACCELEROMETER_EVT_FACE_DOWN                6
 #define MICROBIT_ACCELEROMETER_EVT_FREEFALL                 7
-#define MICROBIT_ACCELEROMETER_EVT_3G                       8    
+#define MICROBIT_ACCELEROMETER_EVT_3G                       8
 #define MICROBIT_ACCELEROMETER_EVT_6G                       9
 #define MICROBIT_ACCELEROMETER_EVT_8G                       10
 #define MICROBIT_ACCELEROMETER_EVT_SHAKE                    11
@@ -140,10 +140,10 @@ struct ShakeHistory
 class MicroBitAccelerometer : public MicroBitComponent
 {
     /**
-      * Unique, enumerated ID for this component. 
+      * Unique, enumerated ID for this component.
       * Used to track asynchronous events in the event bus.
       */
-    
+
     uint16_t        address;            // I2C address of this accelerometer.
     uint16_t        samplePeriod;       // The time between samples, in milliseconds.
     uint8_t         sampleRange;        // The sample range of the accelerometer in g.
@@ -152,20 +152,20 @@ class MicroBitAccelerometer : public MicroBitComponent
     float           pitch;              // Pitch of the device, in radians.
     float           roll;               // Roll of the device, in radians.
     uint8_t         sigma;              // the number of ticks that the instantaneous gesture has been stable.
-    BasicGesture    lastGesture;        // the last, stable gesture recorded. 
+    BasicGesture    lastGesture;        // the last, stable gesture recorded.
     BasicGesture    currentGesture;     // the instantaneous, unfiltered gesture detected.
     ShakeHistory    shake;              // State information needed to detect shake events.
-    
+
     public:
 
     /**
-     * Constructor. 
+     * Constructor.
      * Create an accelerometer representation with the given ID.
      * @param id the ID of the new object.
-     * @param address the default base address of the accelerometer. 
+     * @param address the default base address of the accelerometer.
      *
      * Example:
-     * @code 
+     * @code
      * accelerometer(MICROBIT_ID_ACCELEROMETER, MMA8653_DEFAULT_ADDR)
      * @endcode
      */
@@ -199,7 +199,7 @@ class MicroBitAccelerometer : public MicroBitComponent
     int setPeriod(int period);
 
     /**
-     * Reads the currently configured sample rate of the accelerometer. 
+     * Reads the currently configured sample rate of the accelerometer.
      * @return The time between samples, in milliseconds.
      */
     int getPeriod();
@@ -214,17 +214,17 @@ class MicroBitAccelerometer : public MicroBitComponent
     int setRange(int range);
 
     /**
-     * Reads the currently configured sample range of the accelerometer. 
+     * Reads the currently configured sample range of the accelerometer.
      * @return The sample range, in g.
      */
     int getRange();
 
     /**
-     * Attempts to determine the 8 bit ID from the accelerometer. 
+     * Attempts to determine the 8 bit ID from the accelerometer.
      * @return the 8 bit ID returned by the accelerometer, or MICROBIT_I2C_ERROR if the request fails.
      *
      * Example:
-     * @code 
+     * @code
      * uBit.accelerometer.whoAmI();
      * @endcode
      */
@@ -236,32 +236,32 @@ class MicroBitAccelerometer : public MicroBitComponent
       * @return The force measured in the X axis, in milli-g.
       *
       * Example:
-      * @code 
+      * @code
       * uBit.accelerometer.getX();
       * @endcode
       */
     int getX(MicroBitCoordinateSystem system = SIMPLE_CARTESIAN);
-    
+
     /**
       * Reads the Y axis value of the latest update from the accelerometer.
       * @return The force measured in the Y axis, in milli-g.
       *
       * Example:
-      * @code 
+      * @code
       * uBit.accelerometer.getY();
       * @endcode
-      */    
+      */
     int getY(MicroBitCoordinateSystem system = SIMPLE_CARTESIAN);
-    
+
     /**
       * Reads the Z axis value of the latest update from the accelerometer.
       * @return The force measured in the Z axis, in milli-g.
       *
       * Example:
-      * @code 
+      * @code
       * uBit.accelerometer.getZ();
       * @endcode
-      */    
+      */
     int getZ(MicroBitCoordinateSystem system = SIMPLE_CARTESIAN);
 
     /**
@@ -269,10 +269,10 @@ class MicroBitAccelerometer : public MicroBitComponent
       * @return The pitch of the device, in degrees.
       *
       * Example:
-      * @code 
+      * @code
       * uBit.accelerometer.getPitch();
       * @endcode
-      */    
+      */
     int getPitch();
     float getPitchRadians();
 
@@ -281,10 +281,10 @@ class MicroBitAccelerometer : public MicroBitComponent
       * @return The roll of the device, in degrees.
       *
       * Example:
-      * @code 
+      * @code
       * uBit.accelerometer.getRoll();
       * @endcode
-      */    
+      */
     int getRoll();
     float getRollRadians();
 
@@ -293,16 +293,16 @@ class MicroBitAccelerometer : public MicroBitComponent
      * @return The last gesture detected.
      *
      * Example:
-     * @code 
+     * @code
      * if (uBit.accelerometer.getGesture() == SHAKE)
      * @endcode
-     */    
+     */
     BasicGesture getGesture();
 
     /**
      * periodic callback from MicroBit idle thread.
      * Check if any data is ready for reading by checking the interrupt flag on the accelerometer
-     */    
+     */
     virtual void idleTick();
 
     /**
@@ -310,6 +310,11 @@ class MicroBitAccelerometer : public MicroBitComponent
      */
     virtual int isIdleCallbackNeeded();
 
+    /**
+      * Destructor for MicroBitButton, so that we deregister ourselves as an idleComponent
+      */
+    ~MicroBitAccelerometer();
+
     private:
     /**
      * Issues a standard, 2 byte I2C command write to the accelerometer.
@@ -341,7 +346,7 @@ class MicroBitAccelerometer : public MicroBitComponent
 
     /**
      *
-     * Updates the basic gesture recognizer. This performs instantaneous pose recognition, and also some low pass filtering to promote 
+     * Updates the basic gesture recognizer. This performs instantaneous pose recognition, and also some low pass filtering to promote
      * stability.
      */
     void updateGesture();
diff --git a/inc/MicroBitButton.h b/inc/MicroBitButton.h
index 59370d4..abc50df 100644
--- a/inc/MicroBitButton.h
+++ b/inc/MicroBitButton.h
@@ -17,8 +17,8 @@
 #define MICROBIT_BUTTON_EVT_HOLD                5
 #define MICROBIT_BUTTON_EVT_DOUBLE_CLICK        6
 
-#define MICROBIT_BUTTON_LONG_CLICK_TIME         1000  
-#define MICROBIT_BUTTON_HOLD_TIME               1500  
+#define MICROBIT_BUTTON_LONG_CLICK_TIME         1000
+#define MICROBIT_BUTTON_HOLD_TIME               1500
 
 #define MICROBIT_BUTTON_STATE                   1
 #define MICROBIT_BUTTON_STATE_HOLD_TRIGGERED    2
@@ -47,27 +47,27 @@ class MicroBitButton : public MicroBitComponent
 {
     PinName name;                                           // mbed pin name of this pin.
     DigitalIn pin;                                          // The mbed object looking after this pin at any point in time (may change!).
-    
+
     unsigned long downStartTime;                            // used to store the current system clock when a button down event occurs
     uint8_t sigma;                                          // integration of samples over time. We use this for debouncing, and noise tolerance for touch sensing
     MicroBitButtonEventConfiguration eventConfiguration;    // Do we want to generate high level event (clicks), or defer this to another service.
-    
+
     public:
 
     /**
-      * Constructor. 
+      * Constructor.
       * Create a pin representation with the given ID.
       * @param id the ID of the new MicroBitButton object.
       * @param name the physical pin on the processor that this butotn is connected to.
       * @param mode the configuration of internal pullups/pulldowns, as define in the mbed PinMode class. PullNone by default.
       *
       * Example:
-      * @code 
+      * @code
       * buttonA(MICROBIT_ID_BUTTON_A,MICROBIT_PIN_BUTTON_A); //a number between 0 and 200 inclusive
       * @endcode
       *
       * Possible Events:
-      * @code 
+      * @code
       * MICROBIT_BUTTON_EVT_DOWN
       * MICROBIT_BUTTON_EVT_UP
       * MICROBIT_BUTTON_EVT_CLICK
@@ -77,25 +77,29 @@ class MicroBitButton : public MicroBitComponent
       * @endcode
       */
     MicroBitButton(uint16_t id, PinName name, MicroBitButtonEventConfiguration eventConfiguration = MICROBIT_BUTTON_ALL_EVENTS, PinMode mode = PullNone);
-    
+
     /**
       * Tests if this Button is currently pressed.
       * @return 1 if this button is pressed, 0 otherwise.
       *
       * Example:
-      * @code 
+      * @code
       * if(uBit.buttonA.isPressed())
       *     print("Pressed!");
       * @endcode
       */
     int isPressed();
-    
+
     /**
       * periodic callback from MicroBit clock.
       * Check for state change for this button, and fires a hold event if button is pressed.
-      */  
+      */
     virtual void systemTick();
-    
+
+    /**
+      * Destructor for MicroBitButton, so that we deregister ourselves as a systemComponent
+      */
+    ~MicroBitButton();
 };
 
 #endif
diff --git a/inc/MicroBitCompass.h b/inc/MicroBitCompass.h
index a294c65..37b96ce 100644
--- a/inc/MicroBitCompass.h
+++ b/inc/MicroBitCompass.h
@@ -48,7 +48,7 @@ struct MAG3110SampleRateConfig
 
 extern const MAG3110SampleRateConfig MAG3110SampleRate[];
 
-#define MAG3110_SAMPLE_RATES                    11 
+#define MAG3110_SAMPLE_RATES                    11
 
 /*
  * Compass events
@@ -66,7 +66,7 @@ extern const MAG3110SampleRateConfig MAG3110SampleRate[];
  */
 #define MICROBIT_COMPASS_STATUS_CALIBRATED      1
 #define MICROBIT_COMPASS_STATUS_CALIBRATING     2
- 
+
 /*
  * Term to convert sample data into SI units
  */
@@ -83,19 +83,19 @@ struct CompassSample
     int     x;
     int     y;
     int     z;
-    
+
     CompassSample()
     {
         this->x = 0;
         this->y = 0;
-        this->z = 0;   
+        this->z = 0;
     }
 
     CompassSample(int x, int y, int z)
     {
         this->x = x;
         this->y = y;
-        this->z = z;   
+        this->z = z;
     }
 };
 
@@ -108,11 +108,11 @@ struct CompassSample
 class MicroBitCompass : public MicroBitComponent
 {
     /**
-      * Unique, enumerated ID for this component. 
+      * Unique, enumerated ID for this component.
       * Used to track asynchronous events in the event bus.
       */
-      
-    uint16_t            address;                  // I2C address of the magnetmometer.  
+
+    uint16_t            address;                  // I2C address of the magnetmometer.
     uint16_t            samplePeriod;             // The time between samples, in millseconds.
 
     CompassSample       average;                  // Centre point of sample data.
@@ -120,9 +120,9 @@ class MicroBitCompass : public MicroBitComponent
     DigitalIn           int1;                     // Data ready interrupt.
 
     public:
-            
+
     /**
-      * Constructor. 
+      * Constructor.
       * Create a compass representation with the given ID.
       * @param id the event ID of the compass object.
       * @param address the default address for the compass register
@@ -140,7 +140,7 @@ class MicroBitCompass : public MicroBitComponent
       * @endcode
       */
     MicroBitCompass(uint16_t id, uint16_t address);
-   
+
     /**
      * Configures the compass for the sample rate defined
      * in this object. The nearest values are chosen to those defined
@@ -160,7 +160,7 @@ class MicroBitCompass : public MicroBitComponent
     int setPeriod(int period);
 
     /**
-      * Reads the currently configured sample rate of the compass. 
+      * Reads the currently configured sample rate of the compass.
       * @return The time between samples, in milliseconds.
       */
     int getPeriod();
@@ -169,10 +169,10 @@ class MicroBitCompass : public MicroBitComponent
      * Gets the current heading of the device, relative to magnetic north.
      * If the compass is not calibrated, it will raise the MICROBIT_COMPASS_EVT_CALIBRATE event.
      * Users wishing to implement their own calibration algorithms should listen for this event,
-     * using MESSAGE_BUS_LISTENER_IMMEDIATE model. This ensures that calibration is complete before 
-     * the user program continues. 
-     * 
-     * @return the current heading, in degrees. Or MICROBIT_CALIBRATION_IN_PROGRESS if the compass is calibrating. 
+     * using MESSAGE_BUS_LISTENER_IMMEDIATE model. This ensures that calibration is complete before
+     * the user program continues.
+     *
+     * @return the current heading, in degrees. Or MICROBIT_CALIBRATION_IN_PROGRESS if the compass is calibrating.
      *
      * Example:
      * @code
@@ -182,7 +182,7 @@ class MicroBitCompass : public MicroBitComponent
     int heading();
 
     /**
-      * Attempts to determine the 8 bit ID from the magnetometer. 
+      * Attempts to determine the 8 bit ID from the magnetometer.
       * @return the id of the compass (magnetometer), or MICROBIT_I2C_ERROR if the magnetometer could not be updated.
       *
       * Example:
@@ -202,7 +202,7 @@ class MicroBitCompass : public MicroBitComponent
      * @endcode
      */
     int getX(MicroBitCoordinateSystem system = SIMPLE_CARTESIAN);
-    
+
     /**
      * Reads the Y axis value of the latest update from the compass.
      * @return The magnetic force measured in the Y axis, in nano teslas.
@@ -211,9 +211,9 @@ class MicroBitCompass : public MicroBitComponent
      * @code
      * uBit.compass.getY();
      * @endcode
-     */     
+     */
     int getY(MicroBitCoordinateSystem system = SIMPLE_CARTESIAN);
-    
+
     /**
      * Reads the Z axis value of the latest update from the compass.
      * @return The magnetic force measured in the Z axis, in nano teslas.
@@ -222,8 +222,8 @@ class MicroBitCompass : public MicroBitComponent
      * @code
      * uBit.compass.getZ();
      * @endcode
-     */     
-    int getZ(MicroBitCoordinateSystem system = SIMPLE_CARTESIAN);    
+     */
+    int getZ(MicroBitCoordinateSystem system = SIMPLE_CARTESIAN);
 
     /**
      * Determines the overall magnetic field strength based on the latest update from the compass.
@@ -233,21 +233,21 @@ class MicroBitCompass : public MicroBitComponent
      * @code
      * uBit.compass.getFieldStrength();
      * @endcode
-     */     
+     */
     int getFieldStrength();
 
     /**
-      * Reads the current die temperature of the compass. 
+      * Reads the current die temperature of the compass.
       * @return the temperature in degrees celsius, or MICROBIT_I2C_ERROR if the magnetometer could not be updated.
       */
     int readTemperature();
 
     /**
      * Perform a calibration of the compass.
-     * 
+     *
      * This method will be called automatically if a user attempts to read a compass value when
      * the compass is uncalibrated. It can also be called at any time by the user.
-     * 
+     *
      * Any old calibration data is deleted.
      * The method will only return once the compass has been calibrated.
      *
@@ -265,7 +265,7 @@ class MicroBitCompass : public MicroBitComponent
       * @note *** THIS FUNCITON IS NOW DEPRECATED AND WILL BE REMOVED IN THE NEXT MAJOR RELEASE ***
       * @note *** PLEASE USE THE calibrate() FUNCTION INSTEAD ***
       */
-    void calibrateAsync();  
+    void calibrateAsync();
 
     /**
       * Perform a calibration of the compass.
@@ -274,62 +274,67 @@ class MicroBitCompass : public MicroBitComponent
       * @note *** THIS FUNCITON IS NOW DEPRECATED AND WILL BE REMOVED IN THE NEXT MAJOR RELEASE ***
       * @note *** PLEASE USE THE calibrate() FUNCTION INSTEAD ***
       */
-    int calibrateStart();    
+    int calibrateStart();
 
     /**
       * Complete the calibration of the compass.
       * This will fire MICROBIT_COMPASS_EVT_CAL_END.
       *
       * @note *** THIS FUNCITON IS NOW DEPRECATED AND WILL BE REMOVED IN THE NEXT MAJOR RELEASE ***
-      */    
-    void calibrateEnd();    
+      */
+    void calibrateEnd();
 
     /**
      * Configure the compass to use the given calibration data.
      * Calibration data is comprised of the perceived zero offset of each axis of the compass.
-     * After calibration this should now take into account trimming errors in the magnetometer, 
+     * After calibration this should now take into account trimming errors in the magnetometer,
      * and any "hard iron" offsets on the device.
      *
      * @param The x, y and z zero offsets to use as calibration data.
-     */     
+     */
     void setCalibration(CompassSample calibration);
 
     /**
      * Provides the calibration data currently in use by the compass.
      * More specifically, the x, y and z zero offsets of the compass.
      *
-     * @return The x, y and z xero offsets of the compass. 
-     */     
+     * @return The x, y and z xero offsets of the compass.
+     */
     CompassSample getCalibration();
 
     /**
       * Periodic callback from MicroBit idle thread.
       * Check if any data is ready for reading by checking the interrupt.
-      */  
+      */
     virtual void idleTick();
-    
+
     /**
       * Returns 0 or 1. 1 indicates that the compass is calibrated, zero means the compass requires calibration.
       */
     int isCalibrated();
-    
+
     /**
       * Returns 0 or 1. 1 indicates that the compass is calibrating, zero means the compass is not currently calibrating.
       */
     int isCalibrating();
-    
+
     /**
       * Clears the calibration held in persistent storage, and sets the calibrated flag to zero.
       */
     void clearCalibration();
-    
+
     /**
       * Returns 0 or 1. 1 indicates data is waiting to be read, zero means data is not ready to be read.
       */
     virtual int isIdleCallbackNeeded();
-    
+
+    /**
+      * Destructor for MicroBitCompass, so that we deregister ourselves as an idleComponent
+      */
+    ~MicroBitCompass();
+
     private:
-    
+
     /**
       * Issues a standard, 2 byte I2C command write to the magnetometer.
       * Blocks the calling thread until complete.
@@ -339,7 +344,7 @@ class MicroBitCompass : public MicroBitComponent
       * @return MICROBIT_OK on success, MICROBIT_I2C_ERROR if the magnetometer could not be accessed.
       */
     int writeCommand(uint8_t reg, uint8_t value);
-    
+
     /**
       * Issues a read command into the specified buffer.
       * Blocks the calling thread until complete.
@@ -350,7 +355,7 @@ class MicroBitCompass : public MicroBitComponent
       * @return MICROBIT_OK on success, MICROBIT_INVALID_PARAMETER or MICROBIT_I2C_ERROR if the magnetometer could not be accessed.
       */
     int readCommand(uint8_t reg, uint8_t* buffer, int length);
-    
+
     /**
       * Issues a read of a given address, and returns the value.
       * Blocks the calling thread until complete.
@@ -359,8 +364,8 @@ class MicroBitCompass : public MicroBitComponent
       * @return The register value, interpreted as a 16 but signed value, or MICROBIT_I2C_ERROR if the magnetometer could not be accessed.
       */
     int read16(uint8_t reg);
-    
-    
+
+
     /**
       * Issues a read of a given address, and returns the value.
       * Blocks the calling thread until complete.
diff --git a/inc/MicroBitDisplay.h b/inc/MicroBitDisplay.h
index 86e6dd3..539569b 100644
--- a/inc/MicroBitDisplay.h
+++ b/inc/MicroBitDisplay.h
@@ -73,7 +73,7 @@ enum AnimationMode {
 
 enum DisplayMode {
     DISPLAY_MODE_BLACK_AND_WHITE,
-    DISPLAY_MODE_GREYSCALE    
+    DISPLAY_MODE_GREYSCALE
 };
 
 enum DisplayRotation {
@@ -172,24 +172,24 @@ class MicroBitDisplay : public MicroBitComponent
       *  Periodic callback, that we use to perform any animations we have running.
       */
     void animationUpdate();
-    
+
     /**
       *  Called by the display in an interval determined by the brightness of the display, to give an impression
       *  of brightness.
       */
     void renderFinish();
-    
+
     /**
       * Translates a bit mask to a bit mask suitable for the nrf PORT0 and PORT1.
       * Brightness has two levels on, or off.
       */
     void render();
-    
+
     /**
       * Translates a bit mask into a timer interrupt that gives the appearence of greyscale.
       */
     void renderGreyscale();
-    
+
     /**
       * Internal scrollText update method.
       * Shift the screen image by one pixel to the left. If necessary, paste in the next char.
@@ -224,7 +224,7 @@ class MicroBitDisplay : public MicroBitComponent
     /**
       * Blocks the current fiber until the display is available (i.e. not effect is being displayed).
       * Animations are queued until their time to display.
-      */ 
+      */
     void waitForFreeDisplay();
 
 public:
@@ -255,16 +255,16 @@ public:
       * Frame update method, invoked periodically to strobe the display.
       */
     virtual void systemTick();
-    
+
     /**
      * Prints the given character to the display, if it is not in use.
      *
      * @param c The character to display.
      * @param delay Optional parameter - the time for which to show the character. Zero displays the character forever.
      * @return MICROBIT_OK, MICROBIT_BUSY is the screen is in use, or MICROBIT_INVALID_PARAMETER.
-     * 
+     *
      * Example:
-     * @code 
+     * @code
      * uBit.display.printAsync('p');
      * uBit.display.printAsync('p',100);
      * @endcode
@@ -294,7 +294,7 @@ public:
      * @param i The image to display.
      * @param x The horizontal position on the screen to display the image (default 0)
      * @param y The vertical position on the screen to display the image (default 0)
-     * @param alpha Treats the brightness level '0' as transparent (default 0) 
+     * @param alpha Treats the brightness level '0' as transparent (default 0)
      * @param delay The time to delay between characters, in milliseconds. set to 0 to display forever. (default 0).
      *
      * Example:
@@ -334,7 +334,7 @@ public:
       * @endcode
       */
     int print(ManagedString s, int delay = MICROBIT_DEFAULT_PRINT_SPEED);
-    
+
     /**
       * Prints the given image to the display.
       * Blocks the calling thread until all the text has been displayed.
@@ -350,7 +350,7 @@ public:
       * @endcode
       */
     int print(MicroBitImage i, int x, int y, int alpha, int delay = 0);
-    
+
     /**
       * Scrolls the given string to the display, from right to left.
       * Uses the given delay between characters.
@@ -474,14 +474,14 @@ public:
     /**
       * Sets the mode of the display.
       * @param mode The mode to swap the display into. (can be either DISPLAY_MODE_GREYSCALE, or DISPLAY_MODE_NORMAL)
-      * 
+      *
       * Example:
-      * @code 
+      * @code
       * uBit.display.setDisplayMode(DISPLAY_MODE_GREYSCALE); //per pixel brightness
       * @endcode
-      */  
+      */
     void setDisplayMode(DisplayMode mode);
-    
+
     /**
       * Fetches the current brightness of this display.
       * @return the brightness of this display, in the range 0..255.
@@ -557,12 +557,16 @@ public:
       * Retreives the font object used for rendering characters on the display.
       */
     MicroBitFont getFont();
-    
+
     /**
       * Captures the bitmap currently being rendered on the display.
       */
     MicroBitImage screenShot();
+
+    /**
+      * Destructor for MicroBitDisplay, so that we deregister ourselves as a systemComponent
+      */
+    ~MicroBitDisplay();
 };
 
 #endif
-
diff --git a/inc/MicroBitMessageBus.h b/inc/MicroBitMessageBus.h
index abd38f7..8cf63c3 100644
--- a/inc/MicroBitMessageBus.h
+++ b/inc/MicroBitMessageBus.h
@@ -18,7 +18,7 @@
   * MicroBit platform. It serves a number of purposes:
   *
   * 1) It provides an eventing abstraction that is independent of the underlying substrate.
-  * 2) It provides a mechanism to decouple user code from trusted system code 
+  * 2) It provides a mechanism to decouple user code from trusted system code
   *    i.e. the basis of a message passing nano kernel.
   * 3) It allows a common high level eventing abstraction across a range of hardware types.e.g. buttons, BLE...
   * 4) It provides a mechanims for extensibility - new devices added via I/O pins can have OO based
@@ -34,23 +34,23 @@ class MicroBitMessageBus : public MicroBitComponent
     public:
 
 	/**
-	  * Default constructor. 
+	  * Default constructor.
 	  * Anticipating only one MessageBus per device, as filtering is handled within the class.
 	  */
-    MicroBitMessageBus();    
+    MicroBitMessageBus();
 
 	/**
 	  * Queues the given event to be sent to all registered recipients.
 	  *
-	  * @param The event to send. 
+	  * @param The event to send.
 	  *
 	  * n.b. THIS IS NOW WRAPPED BY THE MicroBitEvent CLASS FOR CONVENIENCE...
 	  *
 	  * Example:
-      * @code 
+      * @code
 	  * MicroBitEvent evt(id,MICROBIT_BUTTON_EVT_DOWN,ticks,false);
 	  * evt.fire();
-	  * //OR YOU CAN DO THIS...  
+	  * //OR YOU CAN DO THIS...
 	  * MicroBitEvent evt(id,MICROBIT_BUTTON_EVT_DOWN);
       * @endcode
 	  */
@@ -63,7 +63,7 @@ class MicroBitMessageBus : public MicroBitComponent
       * IT IS RECOMMENDED THAT ALL EXTERNAL CODE USE THE send() FUNCTIONS INSTEAD OF THIS FUNCTION,
       * or the constructors provided by MicroBitEvent.
 	  *
-	  * @param evt The event to send. 
+	  * @param evt The event to send.
       * @param urgent The type of listeners to process (optional). If set to true, only listeners defined as urgent and non-blocking will be processed
       * otherwise, all other (standard) listeners will be processed.
       * @return 1 if all matching listeners were processed, 0 if further processing is required.
@@ -72,19 +72,19 @@ class MicroBitMessageBus : public MicroBitComponent
 
 	/**
 	  * Register a listener function.
-	  * 
-	  * @param id The source of messages to listen for. Events sent from any other IDs will be filtered. 
+	  *
+	  * @param id The source of messages to listen for. Events sent from any other IDs will be filtered.
 	  * Use MICROBIT_ID_ANY to receive events from all components.
 	  *
-	  * @param value The value of messages to listen for. Events with any other values will be filtered. 
+	  * @param value The value of messages to listen for. Events with any other values will be filtered.
 	  * Use MICROBIT_EVT_ANY to receive events of any value.
 	  *
 	  * @param handler The function to call when an event is received.
       *
       * @return MICROBIT_OK on success MICROBIT_INVALID_PARAMETER
-	  * 
+	  *
       * Example:
-      * @code 
+      * @code
       * void onButtonBClick()
       * {
       * 	//do something
@@ -93,22 +93,22 @@ class MicroBitMessageBus : public MicroBitComponent
       * @endcode
 	  */
 	int listen(int id, int value, void (*handler)(MicroBitEvent), uint16_t flags = MESSAGE_BUS_LISTENER_DEFAULT_FLAGS);
-	
+
 	/**
 	  * Register a listener function.
-	  * 
-	  * @param id The source of messages to listen for. Events sent from any other IDs will be filtered. 
+	  *
+	  * @param id The source of messages to listen for. Events sent from any other IDs will be filtered.
 	  * Use MICROBIT_ID_ANY to receive events from all components.
 	  *
-	  * @param value The value of messages to listen for. Events with any other values will be filtered. 
+	  * @param value The value of messages to listen for. Events with any other values will be filtered.
 	  * Use MICROBIT_EVT_ANY to receive events of any value.
 	  *
 	  * @param hander The function to call when an event is received.
       *
       * @return MICROBIT_OK on success MICROBIT_INVALID_PARAMETER
-	  * 
+	  *
       * Example:
-      * @code 
+      * @code
       * void onButtonBClick(void *arg)
       * {
       * 	//do something
@@ -120,26 +120,26 @@ class MicroBitMessageBus : public MicroBitComponent
 
 	/**
 	  * Register a listener function.
-	  * 
-	  * @param id The source of messages to listen for. Events sent from any other IDs will be filtered. 
+	  *
+	  * @param id The source of messages to listen for. Events sent from any other IDs will be filtered.
 	  * Use MICROBIT_ID_ANY to receive events from all components.
 	  *
-	  * @param value The value of messages to listen for. Events with any other values will be filtered. 
+	  * @param value The value of messages to listen for. Events with any other values will be filtered.
 	  * Use MICROBIT_EVT_ANY to receive events of any value.
 	  *
 	  * @param hander The function to call when an event is received.
       *
       * @return MICROBIT_OK on success MICROBIT_INVALID_PARAMETER
-	  * 
+	  *
       * Example:
-      * @code 
+      * @code
       * void SomeClass::onButtonBClick()
       * {
       * 	//do something
       * }
       *
       * SomeClass s = new SomeClass();
-      * uBit.MessageBus.listen(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, s, &SomeClass::onButtonBClick); 
+      * uBit.MessageBus.listen(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, s, &SomeClass::onButtonBClick);
       * @endcode
 	  */
     template <typename T>
@@ -149,7 +149,7 @@ class MicroBitMessageBus : public MicroBitComponent
 	/**
 	  * Unregister a listener function.
       * Listners are identified by the Event ID, Event VALUE and handler registered using listen().
-	  * 
+	  *
 	  * @param id The Event ID used to register the listener.
 	  * @param value The Event VALUE used to register the listener.
 	  * @param handler The function used to register the listener.
@@ -158,21 +158,21 @@ class MicroBitMessageBus : public MicroBitComponent
       *
 	  *
       * Example:
-      * @code 
+      * @code
       * void onButtonBClick()
       * {
       * 	//do something
       * }
       *
-      * uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, onButtonBClick); 
+      * uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, onButtonBClick);
       * @endcode
 	  */
 	int ignore(int id, int value, void (*handler)(MicroBitEvent));
-	
+
 	/**
 	  * Unregister a listener function.
       * Listners are identified by the Event ID, Event VALUE and handler registered using listen().
-	  * 
+	  *
 	  * @param id The Event ID used to register the listener.
 	  * @param value The Event VALUE used to register the listener.
 	  * @param handler The function used to register the listener.
@@ -180,13 +180,13 @@ class MicroBitMessageBus : public MicroBitComponent
       * @return MICROBIT_OK on success MICROBIT_INVALID_PARAMETER
 	  *
       * Example:
-      * @code 
+      * @code
       * void onButtonBClick(void *arg)
       * {
       * 	//do something
       * }
       *
-      * uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, onButtonBClick); 
+      * uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, onButtonBClick);
       * @endcode
 	  */
 	int ignore(int id, int value, void (*handler)(MicroBitEvent, void*));
@@ -194,7 +194,7 @@ class MicroBitMessageBus : public MicroBitComponent
 	/**
 	  * Unregister a listener function.
       * Listners are identified by the Event ID, Event VALUE and handler registered using listen().
-	  * 
+	  *
 	  * @param id The Event ID used to register the listener.
 	  * @param value The Event VALUE used to register the listener.
 	  * @param handler The function used to register the listener.
@@ -202,15 +202,15 @@ class MicroBitMessageBus : public MicroBitComponent
       * @return MICROBIT_OK on success MICROBIT_INVALID_PARAMETER
 	  *
       * Example:
-      * @code 
-      * 
+      * @code
+      *
       * void SomeClass::onButtonBClick()
       * {
       * 	//do something
       * }
       *
       * SomeClass s = new SomeClass();
-      * uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, s, &SomeClass::onButtonBClick); 
+      * uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, s, &SomeClass::onButtonBClick);
       * @endcode
 	  */
     template <typename T>
@@ -223,6 +223,11 @@ class MicroBitMessageBus : public MicroBitComponent
       */
     MicroBitListener *elementAt(int n);
 
+    /**
+      * Destructor for MicroBitMessageBus, so that we deregister ourselves as an idleComponent
+      */
+    ~MicroBitMessageBus();
+
 	private:
 
     /**
@@ -250,7 +255,7 @@ class MicroBitMessageBus : public MicroBitComponent
     MicroBitEventQueueItem      *evt_queue_tail;    // Tail of queued events to be processed.
     uint16_t                    nonce_val;          // The last nonce issued.
     uint16_t                    queueLength;        // The number of events currently waiting to be processed.
-            
+
     void queueEvent(MicroBitEvent &evt);
     MicroBitEventQueueItem* dequeueEvent();
 
@@ -262,10 +267,10 @@ class MicroBitMessageBus : public MicroBitComponent
   * A registration function to allow C++ member funcitons (methods) to be registered as an event
   * listener.
   *
-  * @param id The source of messages to listen for. Events sent from any other IDs will be filtered. 
+  * @param id The source of messages to listen for. Events sent from any other IDs will be filtered.
   * Use MICROBIT_ID_ANY to receive events from all components.
   *
-  * @param value The value of messages to listen for. Events with any other values will be filtered. 
+  * @param value The value of messages to listen for. Events with any other values will be filtered.
   * Use MICROBIT_EVT_ANY to receive events of any value.
   *
   * @param object The object on which the method should be invoked.
@@ -291,7 +296,7 @@ int MicroBitMessageBus::listen(uint16_t id, uint16_t value, T* object, void (T::
 /**
  * Unregister a listener function.
  * Listners are identified by the Event ID, Event VALUE and handler registered using listen().
- * 
+ *
  * @param id The Event ID used to register the listener.
  * @param value The Event VALUE used to register the listener.
  * @param handler The function used to register the listener.
@@ -299,13 +304,13 @@ int MicroBitMessageBus::listen(uint16_t id, uint16_t value, T* object, void (T::
  * @return MICROBIT_OK on success MICROBIT_INVALID_PARAMETER
  *
  * Example:
- * @code 
+ * @code
  * void onButtonBClick(void *arg)
  * {
  * 	//do something
  * }
  *
- * uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, onButtonBClick); 
+ * uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, onButtonBClick);
  * @endcode
  */
 template <typename T>
@@ -322,5 +327,3 @@ int MicroBitMessageBus::ignore(uint16_t id, uint16_t value, T* object, void (T::
 
 
 #endif
-
-
diff --git a/module.json b/module.json
index 13254ee..0d4e6a9 100644
--- a/module.json
+++ b/module.json
@@ -1,6 +1,6 @@
 {
   "name": "microbit-dal",
-  "version": "1.4.4",
+  "version": "1.4.6",
   "license": "Apache2",
   "description": "The runtime library for the BBC micro:bit, developed by Lancaster University",
   "keywords": [
@@ -21,4 +21,4 @@
   "extraIncludes": [
     "inc"
   ]
-}
+}
\ No newline at end of file
diff --git a/source/MicroBit.cpp b/source/MicroBit.cpp
index b0a25dd..ccc0fb7 100644
--- a/source/MicroBit.cpp
+++ b/source/MicroBit.cpp
@@ -5,7 +5,7 @@
   */
 void panic(int statusCode)
 {
-    uBit.panic(statusCode);   
+    uBit.panic(statusCode);
 }
 
 /**
@@ -43,30 +43,30 @@ void bleDisconnectionCallback(const Gap::DisconnectionCallbackParams_t *reason)
 {
     (void) reason; /* -Wunused-param */
 
-    uBit.ble->startAdvertising(); 
+    uBit.ble->startAdvertising();
 }
 
 
 /**
-  * Constructor. 
+  * Constructor.
   * Create a representation of a MicroBit device as a global singleton.
   * @param messageBus callback function to receive MicroBitMessageBus events.
   *
   * Exposed objects:
-  * @code 
+  * @code
   * uBit.systemTicker; //the Ticker callback that performs routines like updating the display.
   * uBit.MessageBus; //The message bus where events are fired.
   * uBit.display; //The display object for the LED matrix.
   * uBit.buttonA; //The buttonA object for button a.
   * uBit.buttonB; //The buttonB object for button b.
-  * uBit.buttonAB; //The buttonAB object for button a+b multi press.  
+  * uBit.buttonAB; //The buttonAB object for button a+b multi press.
   * uBit.resetButton; //The resetButton used for soft resets.
   * uBit.accelerometer; //The object that represents the inbuilt accelerometer
   * uBit.compass; //The object that represents the inbuilt compass(magnetometer)
   * uBit.io.P*; //Where P* is P0 to P16, P19 & P20 on the edge connector
   * @endcode
   */
-MicroBit::MicroBit() : 
+MicroBit::MicroBit() :
     flags(0x00),
     i2c(MICROBIT_PIN_SDA, MICROBIT_PIN_SCL),
     serial(USBTX, USBRX),
@@ -74,7 +74,7 @@ MicroBit::MicroBit() :
     display(MICROBIT_ID_DISPLAY, MICROBIT_DISPLAY_WIDTH, MICROBIT_DISPLAY_HEIGHT),
     buttonA(MICROBIT_ID_BUTTON_A,MICROBIT_PIN_BUTTON_A, MICROBIT_BUTTON_SIMPLE_EVENTS),
     buttonB(MICROBIT_ID_BUTTON_B,MICROBIT_PIN_BUTTON_B, MICROBIT_BUTTON_SIMPLE_EVENTS),
-    buttonAB(MICROBIT_ID_BUTTON_AB,MICROBIT_ID_BUTTON_A,MICROBIT_ID_BUTTON_B), 
+    buttonAB(MICROBIT_ID_BUTTON_AB,MICROBIT_ID_BUTTON_A,MICROBIT_ID_BUTTON_B),
     accelerometer(MICROBIT_ID_ACCELEROMETER, MMA8653_DEFAULT_ADDR),
     compass(MICROBIT_ID_COMPASS, MAG3110_DEFAULT_ADDR),
     thermometer(MICROBIT_ID_THERMOMETER),
@@ -86,25 +86,25 @@ MicroBit::MicroBit() :
        MICROBIT_ID_IO_P15,MICROBIT_ID_IO_P16,MICROBIT_ID_IO_P19,
        MICROBIT_ID_IO_P20),
 	bleManager()
-{   
+{
 }
 
 /**
   * Post constructor initialisation method.
-  * After *MUCH* pain, it's noted that the BLE stack can't be brought up in a 
+  * After *MUCH* pain, it's noted that the BLE stack can't be brought up in a
   * static context, so we bring it up here rather than in the constructor.
   * n.b. This method *must* be called in main() or later, not before.
   *
   * Example:
-  * @code 
+  * @code
   * uBit.init();
   * @endcode
   */
 void MicroBit::init()
-{   
+{
     //add the display to the systemComponent array
     addSystemComponent(&uBit.display);
-    
+
     //add the compass and accelerometer to the idle array
     addIdleComponent(&uBit.accelerometer);
     addIdleComponent(&uBit.compass);
@@ -114,14 +114,14 @@ void MicroBit::init()
     seedRandom();
 
 #if CONFIG_ENABLED(MICROBIT_BLE_ENABLED)
-    // Start the BLE stack.        
+    // Start the BLE stack.
     bleManager.init(this->getName(), this->getSerial());
-	  
+
     ble = bleManager.ble;
 #endif
 
     // Start refreshing the Matrix Display
-    systemTicker.attach(this, &MicroBit::systemTick, MICROBIT_DISPLAY_REFRESH_PERIOD);     
+    systemTicker.attach(this, &MicroBit::systemTick, MICROBIT_DISPLAY_REFRESH_PERIOD);
 
     // Register our compass calibration algorithm.
     MessageBus.listen(MICROBIT_ID_COMPASS, MICROBIT_COMPASS_EVT_CALIBRATE, this, &MicroBit::compassCalibrator, MESSAGE_BUS_LISTENER_IMMEDIATE);
@@ -146,7 +146,7 @@ void MicroBit::compassCalibrator(MicroBitEvent)
     const int PIXEL2_THRESHOLD = 800;
 
 	Matrix4 X(PERIMETER_POINTS, 4);
-    Point perimeter[PERIMETER_POINTS] = {{1,0,0}, {2,0,0}, {3,0,0}, {4,1,0}, {4,2,0}, {4,3,0}, {3,4,0}, {2,4,0}, {1,4,0}, {0,3,0}, {0,2,0}, {0,1,0}}; 
+    Point perimeter[PERIMETER_POINTS] = {{1,0,0}, {2,0,0}, {3,0,0}, {4,1,0}, {4,2,0}, {4,3,0}, {3,4,0}, {2,4,0}, {1,4,0}, {0,3,0}, {0,2,0}, {0,1,0}};
     Point cursor = {2,2,0};
 
     MicroBitImage img(5,5);
@@ -186,7 +186,7 @@ void MicroBit::compassCalibrator(MicroBitEvent)
             cursor.x = 4;
         else if (x > PIXEL1_THRESHOLD)
             cursor.x = 3;
-        else 
+        else
             cursor.x = 2;
 
         if (y < -PIXEL2_THRESHOLD)
@@ -244,13 +244,13 @@ void MicroBit::compassCalibrator(MicroBitEvent)
 		Y.set(i, 0, v);
 	}
 
-    // Now perform a Least Squares Approximation. 
+    // Now perform a Least Squares Approximation.
 	Matrix4 XT = X.transpose();
 	Matrix4 Beta = XT.multiply(X).invert().multiply(XT).multiply(Y);
 
     // The result contains the approximate zero point of each axis, but doubled.
     // Halve each sample, and record this as the compass calibration data.
-    CompassSample cal = {(int)(Beta.get(0,0) / 2), (int)(Beta.get(1,0) / 2), (int)(Beta.get(2,0) / 2)};
+    CompassSample cal ((int)(Beta.get(0,0) / 2), (int)(Beta.get(1,0) / 2), (int)(Beta.get(2,0) / 2));
     compass.setCalibration(cal);
 
     // Show a smiley to indicate that we're done, and continue on with the user program.
@@ -267,11 +267,11 @@ void MicroBit::compassCalibrator(MicroBitEvent)
 ManagedString MicroBit::getName()
 {
     char nameBuffer[MICROBIT_NAME_LENGTH];
-    const uint8_t codebook[MICROBIT_NAME_LENGTH][MICROBIT_NAME_CODE_LETTERS] = 
+    const uint8_t codebook[MICROBIT_NAME_LENGTH][MICROBIT_NAME_CODE_LETTERS] =
     {
-        {'z', 'v', 'g', 'p', 't'},  
+        {'z', 'v', 'g', 'p', 't'},
         {'u', 'o', 'i', 'e', 'a'},
-        {'z', 'v', 'g', 'p', 't'},  
+        {'z', 'v', 'g', 'p', 't'},
         {'u', 'o', 'i', 'e', 'a'},
         {'z', 'v', 'g', 'p', 't'}
     };
@@ -309,7 +309,7 @@ ManagedString MicroBit::getSerial()
     int n1 = NRF_FICR->DEVICEID[1] & 0xffff;
     int n2 = (NRF_FICR->DEVICEID[1] >> 16) & 0xffff;
 
-    // Simply concat the two numbers. 
+    // Simply concat the two numbers.
     ManagedString s1 = ManagedString(n1);
     ManagedString s2 = ManagedString(n2);
 
@@ -320,7 +320,7 @@ ManagedString MicroBit::getSerial()
   * Will reset the micro:bit when called.
   *
   * Example:
-  * @code 
+  * @code
   * uBit.reset();
   * @endcode
   */
@@ -334,15 +334,15 @@ void MicroBit::reset()
   * If the scheduler is running, this will deschedule the current fiber and perform
   * a power efficent, concurrent sleep operation.
   * If the scheduler is disabled or we're running in an interrupt context, this
-  * will revert to a busy wait. 
+  * will revert to a busy wait.
   *
   * @note Values of below below the scheduling period (typical 6ms) tend to lose resolution.
-  * 
+  *
   * @param milliseconds the amount of time, in ms, to wait for. This number cannot be negative.
-  * @return MICROBIT_OK on success, MICROBIT_INVALID_PARAMETER milliseconds is less than zero. 
+  * @return MICROBIT_OK on success, MICROBIT_INVALID_PARAMETER milliseconds is less than zero.
   *
   * Example:
-  * @code 
+  * @code
   * uBit.sleep(20); //sleep for 20ms
   * @endcode
   */
@@ -351,7 +351,7 @@ int MicroBit::sleep(int milliseconds)
     //sanity check, we can't time travel... (yet?)
     if(milliseconds < 0)
         return MICROBIT_INVALID_PARAMETER;
-        
+
     if (flags & MICROBIT_FLAG_SCHEDULER_RUNNING)
         fiber_sleep(milliseconds);
     else
@@ -368,14 +368,14 @@ int MicroBit::sleep(int milliseconds)
   * than the hardware random number generator built int the processor, which takes
   * a long time and uses a lot of energy.
   *
-  * KIDS: You shouldn't use this is the real world to generte cryptographic keys though... 
+  * KIDS: You shouldn't use this is the real world to generte cryptographic keys though...
   * have a think why not. :-)
   *
   * @param max the upper range to generate a number for. This number cannot be negative
   * @return A random, natural number between 0 and the max-1. Or MICROBIT_INVALID_VALUE (defined in ErrorNo.h) if max is <= 0.
   *
   * Example:
-  * @code 
+  * @code
   * uBit.random(200); //a number between 0 and 199
   * @endcode
   */
@@ -395,7 +395,7 @@ int MicroBit::random(int max)
         result = 0;
 		do {
             // Cycle the LFSR (Linear Feedback Shift Register).
-            // We use an optimal sequence with a period of 2^32-1, as defined by Bruce Schneier here (a true legend in the field!), 
+            // We use an optimal sequence with a period of 2^32-1, as defined by Bruce Schneier here (a true legend in the field!),
             // For those interested, it's documented in his paper:
             // "Pseudo-Random Sequence Generator for 32-Bit CPUs: A fast, machine-independent generator for 32-bit Microprocessors"
             // https://www.schneier.com/paper-pseudorandom-sequence.html
@@ -414,7 +414,7 @@ int MicroBit::random(int max)
 			randomValue = rnd;
 
             result = ((result << 1) | (rnd & 0x00000001));
-        } while(m >>= 1); 
+        } while(m >>= 1);
     } while (result > (uint32_t)max);
 
 
@@ -432,21 +432,21 @@ int MicroBit::random(int max)
 void MicroBit::seedRandom()
 {
     randomValue = 0;
-        
+
     // Start the Random number generator. No need to leave it running... I hope. :-)
     NRF_RNG->TASKS_START = 1;
-    
+
     for(int i = 0; i < 4 ;i++)
     {
         // Clear the VALRDY EVENT
         NRF_RNG->EVENTS_VALRDY = 0;
-        
+
         // Wait for a number ot be generated.
         while ( NRF_RNG->EVENTS_VALRDY == 0);
-        
+
         randomValue = (randomValue << 8) | ((int) NRF_RNG->VALUE);
     }
-    
+
     // Disable the generator to save power.
     NRF_RNG->TASKS_STOP = 1;
 }
@@ -456,11 +456,11 @@ void MicroBit::seedRandom()
   * Periodic callback. Used by MicroBitDisplay, FiberScheduler and buttons.
   */
 void MicroBit::systemTick()
-{   
+{
     // Scheduler callback. We do this here just as a single timer is more efficient. :-)
     if (uBit.flags & MICROBIT_FLAG_SCHEDULER_RUNNING)
-        scheduler_tick();  
-    
+        scheduler_tick();
+
     //work out if any idle components need processing, if so prioritise the idle thread
     for(int i = 0; i < MICROBIT_IDLE_COMPONENTS; i++)
         if(idleThreadComponents[i] != NULL && idleThreadComponents[i]->isIdleCallbackNeeded())
@@ -468,7 +468,7 @@ void MicroBit::systemTick()
             fiber_flags |= MICROBIT_FLAG_DATA_READY;
             break;
         }
-        
+
     //update any components in the systemComponents array
     for(int i = 0; i < MICROBIT_SYSTEM_COMPONENTS; i++)
         if(systemTickComponents[i] != NULL)
@@ -479,17 +479,17 @@ void MicroBit::systemTick()
   * System tasks to be executed by the idle thread when the Micro:Bit isn't busy or when data needs to be read.
   */
 void MicroBit::systemTasks()
-{   
-    //call the idleTick member function indiscriminately 
+{
+    //call the idleTick member function indiscriminately
     for(int i = 0; i < MICROBIT_IDLE_COMPONENTS; i++)
         if(idleThreadComponents[i] != NULL)
             idleThreadComponents[i]->idleTick();
-    
+
     fiber_flags &= ~MICROBIT_FLAG_DATA_READY;
 }
 
 /**
-  * add a component to the array of components which invocate the systemTick member function during a systemTick 
+  * add a component to the array of components which invocate the systemTick member function during a systemTick
   * @param component The component to add.
   * @return MICROBIT_OK on success. MICROBIT_NO_RESOURCES is returned if further components cannot be supported.
   * @note this will be converted into a dynamic list of components
@@ -497,14 +497,14 @@ void MicroBit::systemTasks()
 int MicroBit::addSystemComponent(MicroBitComponent *component)
 {
     int i = 0;
-    
-    while(systemTickComponents[i] != NULL && i < MICROBIT_SYSTEM_COMPONENTS)  
+
+    while(systemTickComponents[i] != NULL && i < MICROBIT_SYSTEM_COMPONENTS)
         i++;
-    
+
     if(i == MICROBIT_SYSTEM_COMPONENTS)
         return MICROBIT_NO_RESOURCES;
-        
-    systemTickComponents[i] = component;    
+
+    systemTickComponents[i] = component;
     return MICROBIT_OK;
 }
 
@@ -517,10 +517,10 @@ int MicroBit::addSystemComponent(MicroBitComponent *component)
 int MicroBit::removeSystemComponent(MicroBitComponent *component)
 {
     int i = 0;
-    
-    while(systemTickComponents[i] != component  && i < MICROBIT_SYSTEM_COMPONENTS)  
+
+    while(systemTickComponents[i] != component  && i < MICROBIT_SYSTEM_COMPONENTS)
         i++;
-    
+
     if(i == MICROBIT_SYSTEM_COMPONENTS)
         return MICROBIT_INVALID_PARAMETER;
 
@@ -530,7 +530,7 @@ int MicroBit::removeSystemComponent(MicroBitComponent *component)
 }
 
 /**
-  * add a component to the array of components which invocate the systemTick member function during a systemTick 
+  * add a component to the array of components which invocate the systemTick member function during a systemTick
   * @param component The component to add.
   * @return MICROBIT_OK on success. MICROBIT_NO_RESOURCES is returned if further components cannot be supported.
   * @note this will be converted into a dynamic list of components
@@ -538,14 +538,14 @@ int MicroBit::removeSystemComponent(MicroBitComponent *component)
 int MicroBit::addIdleComponent(MicroBitComponent *component)
 {
     int i = 0;
-    
-    while(idleThreadComponents[i] != NULL && i < MICROBIT_IDLE_COMPONENTS)  
+
+    while(idleThreadComponents[i] != NULL && i < MICROBIT_IDLE_COMPONENTS)
         i++;
-    
+
     if(i == MICROBIT_IDLE_COMPONENTS)
         return MICROBIT_NO_RESOURCES;
-        
-    idleThreadComponents[i] = component;    
+
+    idleThreadComponents[i] = component;
 
     return MICROBIT_OK;
 }
@@ -559,10 +559,10 @@ int MicroBit::addIdleComponent(MicroBitComponent *component)
 int MicroBit::removeIdleComponent(MicroBitComponent *component)
 {
     int i = 0;
-    
-    while(idleThreadComponents[i] != component && i < MICROBIT_IDLE_COMPONENTS)  
+
+    while(idleThreadComponents[i] != component && i < MICROBIT_IDLE_COMPONENTS)
         i++;
-    
+
     if(i == MICROBIT_IDLE_COMPONENTS)
         return MICROBIT_INVALID_PARAMETER;
 
@@ -596,7 +596,7 @@ const char *MicroBit::systemVersion()
 
 /**
   * Triggers a microbit panic where an infinite loop will occur swapping between the panicFace and statusCode if provided.
-  * 
+  *
   * @param statusCode the status code of the associated error. Status codes must be in the range 0-255.
   */
 void MicroBit::panic(int statusCode)
@@ -604,4 +604,3 @@ void MicroBit::panic(int statusCode)
     //show error and enter infinite while
     uBit.display.error(statusCode);
 }
-
diff --git a/source/MicroBitAccelerometer.cpp b/source/MicroBitAccelerometer.cpp
index 4574766..f06fae2 100644
--- a/source/MicroBitAccelerometer.cpp
+++ b/source/MicroBitAccelerometer.cpp
@@ -48,32 +48,32 @@ int MicroBitAccelerometer::configure()
     // Now configure the accelerometer accordingly.
     // First place the device into standby mode, so it can be configured.
     result = writeCommand(MMA8653_CTRL_REG1, 0x00);
-    if (result != 0) 
+    if (result != 0)
         return MICROBIT_I2C_ERROR;
 
     // Enable high precisiosn mode. This consumes a bit more power, but still only 184 uA!
     result = writeCommand(MMA8653_CTRL_REG2, 0x10);
-    if (result != 0) 
+    if (result != 0)
         return MICROBIT_I2C_ERROR;
 
     // Enable the INT1 interrupt pin.
     result = writeCommand(MMA8653_CTRL_REG4, 0x01);
-    if (result != 0) 
+    if (result != 0)
         return MICROBIT_I2C_ERROR;
 
     // Select the DATA_READY event source to be routed to INT1
     result = writeCommand(MMA8653_CTRL_REG5, 0x01);
-    if (result != 0) 
+    if (result != 0)
         return MICROBIT_I2C_ERROR;
 
     // Configure for the selected g range.
     result = writeCommand(MMA8653_XYZ_DATA_CFG, actualSampleRange->xyz_data_cfg);
-    if (result != 0) 
+    if (result != 0)
         return MICROBIT_I2C_ERROR;
 
     // Bring the device back online, with 10bit wide samples at the requested frequency.
     result = writeCommand(MMA8653_CTRL_REG1, actualSampleRate->ctrl_reg1 | 0x01);
-    if (result != 0) 
+    if (result != 0)
         return MICROBIT_I2C_ERROR;
 
     return MICROBIT_OK;
@@ -124,13 +124,13 @@ int MicroBitAccelerometer::readCommand(uint8_t reg, uint8_t* buffer, int length)
 }
 
 /**
- * Constructor. 
+ * Constructor.
  * Create an accelerometer representation with the given ID.
  * @param id the ID of the new object.
- * @param address the default base address of the accelerometer. 
+ * @param address the default base address of the accelerometer.
  *
  * Example:
- * @code 
+ * @code
  * accelerometer(MICROBIT_ID_ACCELEROMETER, MMA8653_DEFAULT_ADDR)
  * @endcode
  */
@@ -161,11 +161,11 @@ MicroBitAccelerometer::MicroBitAccelerometer(uint16_t id, uint16_t address) : sa
 }
 
 /**
- * Attempts to determine the 8 bit ID from the accelerometer. 
+ * Attempts to determine the 8 bit ID from the accelerometer.
  * @return the 8 bit ID returned by the accelerometer, or MICROBIT_I2C_ERROR if the request fails.
  *
  * Example:
- * @code 
+ * @code
  * uBit.accelerometer.whoAmI();
  * @endcode
  */
@@ -174,7 +174,7 @@ int MicroBitAccelerometer::whoAmI()
     uint8_t data;
     int result;
 
-    result = readCommand(MMA8653_WHOAMI, &data, 1);    
+    result = readCommand(MMA8653_WHOAMI, &data, 1);
     if (result !=0)
         return MICROBIT_I2C_ERROR;
 
@@ -197,7 +197,7 @@ int MicroBitAccelerometer::update()
         return MICROBIT_I2C_ERROR;
 
     // read MSB values...
-    sample.x = data[0]; 
+    sample.x = data[0];
     sample.y = data[2];
     sample.z = data[4];
 
@@ -221,7 +221,7 @@ int MicroBitAccelerometer::update()
     // Indicate that pitch and roll data is now stale, and needs to be recalculated if needed.
     status &= ~MICROBIT_ACCEL_PITCH_ROLL_VALID;
 
-    // Update gesture tracking 
+    // Update gesture tracking
     updateGesture();
 
     // Indicate that a new sample is available
@@ -257,9 +257,9 @@ BasicGesture MicroBitAccelerometer::instantaneousPosture()
     // Test for shake events.
     // We detect a shake by measuring zero crossings in each axis. In other words, if we see a strong acceleration to the left followed by
     // a string acceleration to the right, then we can infer a shake. Similarly, we can do this for each acxis (left/right, up/down, in/out).
-    // 
+    //
     // If we see enough zero crossings in succession (MICROBIT_ACCELEROMETER_SHAKE_COUNT_THRESHOLD), then we decide that the device
-    // has been shaken. 
+    // has been shaken.
     if ((getX() < -MICROBIT_ACCELEROMETER_SHAKE_TOLERANCE && shake.x) || (getX() > MICROBIT_ACCELEROMETER_SHAKE_TOLERANCE && !shake.x))
     {
         shakeDetected = true;
@@ -289,7 +289,7 @@ BasicGesture MicroBitAccelerometer::instantaneousPosture()
             if(--shake.count == 0)
                 shake.shaken = 0;
         }
-    }	
+    }
 
     if (shake.shaken)
         return GESTURE_SHAKE;
@@ -334,10 +334,10 @@ void MicroBitAccelerometer::updateGesture()
     BasicGesture g = instantaneousPosture();
 
     // Perform some low pass filtering to reduce jitter from any detected effects
-    if (g == currentGesture)	
+    if (g == currentGesture)
     {
         if (sigma < MICROBIT_ACCELEROMETER_GESTURE_DAMPING)
-            sigma++;	
+            sigma++;
     }
     else
     {
@@ -350,7 +350,7 @@ void MicroBitAccelerometer::updateGesture()
     {
         lastGesture = currentGesture;
         MicroBitEvent e(MICROBIT_ID_GESTURE, lastGesture);
-    }	
+    }
 }
 
 /**
@@ -367,7 +367,7 @@ int MicroBitAccelerometer::setPeriod(int period)
 }
 
 /**
- * Reads the currently configured sample rate of the accelerometer. 
+ * Reads the currently configured sample rate of the accelerometer.
  * @return The time between samples, in milliseconds.
  */
 int MicroBitAccelerometer::getPeriod()
@@ -389,7 +389,7 @@ int MicroBitAccelerometer::setRange(int range)
 }
 
 /**
- * Reads the currently configured sample range of the accelerometer. 
+ * Reads the currently configured sample range of the accelerometer.
  * @return The sample range, in g.
  */
 int MicroBitAccelerometer::getRange()
@@ -403,7 +403,7 @@ int MicroBitAccelerometer::getRange()
   * @return The force measured in the X axis, in milli-g.
   *
   * Example:
-  * @code 
+  * @code
   * uBit.accelerometer.getX();
   * uBit.accelerometer.getX(RAW);
   * @endcode
@@ -414,7 +414,7 @@ int MicroBitAccelerometer::getX(MicroBitCoordinateSystem system)
     {
         case SIMPLE_CARTESIAN:
             return -sample.x;
-                
+
         case NORTH_EAST_DOWN:
             return sample.y;
 
@@ -430,18 +430,18 @@ int MicroBitAccelerometer::getX(MicroBitCoordinateSystem system)
   * @return The force measured in the Y axis, in milli-g.
   *
   * Example:
-  * @code 
+  * @code
   * uBit.accelerometer.getY();
   * uBit.accelerometer.getY(RAW);
   * @endcode
-  */  
+  */
 int MicroBitAccelerometer::getY(MicroBitCoordinateSystem system)
 {
     switch (system)
     {
         case SIMPLE_CARTESIAN:
             return -sample.y;
-                
+
         case NORTH_EAST_DOWN:
             return -sample.x;
 
@@ -457,11 +457,11 @@ int MicroBitAccelerometer::getY(MicroBitCoordinateSystem system)
   * @return The force measured in the Z axis, in milli-g.
   *
   * Example:
-  * @code 
+  * @code
   * uBit.accelerometer.getZ();
   * uBit.accelerometer.getZ(RAW);
   * @endcode
-  */       
+  */
 int MicroBitAccelerometer::getZ(MicroBitCoordinateSystem system)
 {
     switch (system)
@@ -475,16 +475,16 @@ int MicroBitAccelerometer::getZ(MicroBitCoordinateSystem system)
             return sample.z;
     }
 }
-  
+
 /**
   * Provides a rotation compensated pitch of the device, based on the latest update from the accelerometer.
   * @return The pitch of the device, in degrees.
   *
   * Example:
-  * @code 
+  * @code
   * uBit.accelerometer.getPitch();
   * @endcode
-  */    
+  */
 int MicroBitAccelerometer::getPitch()
 {
     return (int) ((360*getPitchRadians()) / (2*PI));
@@ -503,10 +503,10 @@ float MicroBitAccelerometer::getPitchRadians()
   * @return The roll of the device, in degrees.
   *
   * Example:
-  * @code 
+  * @code
   * uBit.accelerometer.getRoll();
   * @endcode
-  */    
+  */
 int MicroBitAccelerometer::getRoll()
 {
     return (int) ((360*getRollRadians()) / (2*PI));
@@ -541,10 +541,10 @@ void MicroBitAccelerometer::recalculatePitchRoll()
  * @return The last gesture detected.
  *
  * Example:
- * @code 
+ * @code
  * if (uBit.accelerometer.getGesture() == SHAKE)
  * @endcode
- */    
+ */
 BasicGesture MicroBitAccelerometer::getGesture()
 {
     return lastGesture;
@@ -553,7 +553,7 @@ BasicGesture MicroBitAccelerometer::getGesture()
 /**
  * periodic callback from MicroBit clock.
  * Check if any data is ready for reading by checking the interrupt flag on the accelerometer
- */  
+ */
 void MicroBitAccelerometer::idleTick()
 {
     // Poll interrupt line from accelerometer.
@@ -571,19 +571,27 @@ int MicroBitAccelerometer::isIdleCallbackNeeded()
     return !int1;
 }
 
+/**
+  * Destructor for MicroBitAccelerometer, so that we deregister ourselves as an idleComponent
+  */
+MicroBitAccelerometer::~MicroBitAccelerometer()
+{
+    uBit.removeIdleComponent(this);
+}
+
 const MMA8653SampleRangeConfig MMA8653SampleRange[MMA8653_SAMPLE_RANGES] = {
-    {2, 0}, 
-    {4, 1}, 
+    {2, 0},
+    {4, 1},
     {8, 2}
 };
 
 const MMA8653SampleRateConfig MMA8653SampleRate[MMA8653_SAMPLE_RATES] = {
-    {1250,      0x00},        
-    {2500,      0x08}, 
-    {5000,      0x10}, 
-    {10000,     0x18}, 
-    {20000,     0x20}, 
-    {80000,     0x28},  
+    {1250,      0x00},
+    {2500,      0x08},
+    {5000,      0x10},
+    {10000,     0x18},
+    {20000,     0x20},
+    {80000,     0x28},
     {160000,    0x30},
     {640000,    0x38}
 };
diff --git a/source/MicroBitButton.cpp b/source/MicroBitButton.cpp
index 1311447..64c211e 100644
--- a/source/MicroBitButton.cpp
+++ b/source/MicroBitButton.cpp
@@ -1,19 +1,19 @@
 #include "MicroBit.h"
 
 /**
-  * Constructor. 
+  * Constructor.
   * Create a pin representation with the given ID.
   * @param id the ID of the new MicroBitButton object.
   * @param name the physical pin on the processor that this butotn is connected to.
   * @param mode the configuration of internal pullups/pulldowns, as define in the mbed PinMode class. PullNone by default.
   *
   * Example:
-  * @code 
+  * @code
   * buttonA(MICROBIT_ID_BUTTON_A,MICROBIT_PIN_BUTTON_A); //a number between 0 and 200 inclusive
   * @endcode
   *
   * Possible Events:
-  * @code 
+  * @code
   * MICROBIT_BUTTON_EVT_DOWN
   * MICROBIT_BUTTON_EVT_UP
   * MICROBIT_BUTTON_EVT_CLICK
@@ -34,9 +34,9 @@ MicroBitButton::MicroBitButton(uint16_t id, PinName name, MicroBitButtonEventCon
 /**
   * periodic callback from MicroBit clock.
   * Check for state change for this button, and fires a hold event if button is pressed.
-  */  
+  */
 void MicroBitButton::systemTick()
-{   
+{
     //
     // If the pin is pulled low (touched), increment our culumative counter.
     // otherwise, decrement it. We're essentially building a lazy follower here.
@@ -45,37 +45,37 @@ void MicroBitButton::systemTick()
     //
     if(!pin)
     {
-        if (sigma < MICROBIT_BUTTON_SIGMA_MAX) 
-            sigma++;  
+        if (sigma < MICROBIT_BUTTON_SIGMA_MAX)
+            sigma++;
     }
     else
     {
-        if (sigma > MICROBIT_BUTTON_SIGMA_MIN) 
+        if (sigma > MICROBIT_BUTTON_SIGMA_MIN)
             sigma--;
     }
-    
+
     // Check to see if we have off->on state change.
     if(sigma > MICROBIT_BUTTON_SIGMA_THRESH_HI && !(status & MICROBIT_BUTTON_STATE))
     {
         // Record we have a state change, and raise an event.
         status |= MICROBIT_BUTTON_STATE;
         MicroBitEvent evt(id,MICROBIT_BUTTON_EVT_DOWN);
-    
+
         //Record the time the button was pressed.
-        downStartTime=ticks;        
+        downStartTime=ticks;
     }
-    
-    // Check to see if we have on->off state change.    
+
+    // Check to see if we have on->off state change.
     if(sigma < MICROBIT_BUTTON_SIGMA_THRESH_LO && (status & MICROBIT_BUTTON_STATE))
     {
         status = 0;
         MicroBitEvent evt(id,MICROBIT_BUTTON_EVT_UP);
-   
+
        if (eventConfiguration == MICROBIT_BUTTON_ALL_EVENTS)
-       { 
+       {
            //determine if this is a long click or a normal click and send event
            if((ticks - downStartTime) >= MICROBIT_BUTTON_LONG_CLICK_TIME)
-               MicroBitEvent evt(id,MICROBIT_BUTTON_EVT_LONG_CLICK);    
+               MicroBitEvent evt(id,MICROBIT_BUTTON_EVT_LONG_CLICK);
            else
                MicroBitEvent evt(id,MICROBIT_BUTTON_EVT_CLICK);
        }
@@ -86,7 +86,7 @@ void MicroBitButton::systemTick()
     {
         //set the hold triggered event flag
         status |= MICROBIT_BUTTON_STATE_HOLD_TRIGGERED;
-        
+
         //fire hold event
         MicroBitEvent evt(id,MICROBIT_BUTTON_EVT_HOLD);
     }
@@ -100,3 +100,11 @@ int MicroBitButton::isPressed()
 {
     return status & MICROBIT_BUTTON_STATE ? 1 : 0;
 }
+
+/**
+  * Destructor for MicroBitButton, so that we deregister ourselves as a systemComponent
+  */
+MicroBitButton::~MicroBitButton()
+{
+    uBit.removeSystemComponent(this);
+}
diff --git a/source/MicroBitCompass.cpp b/source/MicroBitCompass.cpp
index e3610da..d89b6a5 100644
--- a/source/MicroBitCompass.cpp
+++ b/source/MicroBitCompass.cpp
@@ -1,7 +1,7 @@
 #include "MicroBit.h"
 
 /**
-  * Constructor. 
+  * Constructor.
   * Create a compass representation with the given ID.
   * @param id the event ID of the compass object.
   * @param address the default address for the compass register
@@ -22,17 +22,17 @@ MicroBitCompass::MicroBitCompass(uint16_t id, uint16_t address) : average(), sam
 {
     this->id = id;
     this->address = address;
-    
+
     // We presume the device calibrated until the average values are read.
     this->status = 0x01;
 
     // Select 10Hz update rate, with oversampling, and enable the device.
     this->samplePeriod = 100;
     this->configure();
- 
-    // Assume that we have no calibraiton information.   
+
+    // Assume that we have no calibraiton information.
     status &= ~MICROBIT_COMPASS_STATUS_CALIBRATED;
-    
+
     // Indicate that we're up and running.
     uBit.flags |= MICROBIT_FLAG_COMPASS_RUNNING;
 }
@@ -50,7 +50,7 @@ int MicroBitCompass::writeCommand(uint8_t reg, uint8_t value)
     uint8_t command[2];
     command[0] = reg;
     command[1] = value;
-    
+
     return uBit.i2c.write(address, (const char *)command, 2);
 }
 
@@ -100,7 +100,7 @@ int MicroBitCompass::read16(uint8_t reg)
 
     cmd[0] = 0x00;
     cmd[1] = 0x00;
-    
+
     result = uBit.i2c.read(address, (char *)cmd, 2);
     if (result !=0)
         return MICROBIT_I2C_ERROR;
@@ -132,10 +132,10 @@ int MicroBitCompass::read8(uint8_t reg)
  * Gets the current heading of the device, relative to magnetic north.
  * If the compass is not calibrated, it will raise the MICROBIT_COMPASS_EVT_CALIBRATE event.
  * Users wishing to implement their own calibration algorithms should listen for this event,
- * using MESSAGE_BUS_LISTENER_IMMEDIATE model. This ensures that calibration is complete before 
- * the user program continues. 
- * 
- * @return the current heading, in degrees. Or MICROBIT_CALIBRATION_IN_PROGRESS if the compass is calibrating. 
+ * using MESSAGE_BUS_LISTENER_IMMEDIATE model. This ensures that calibration is complete before
+ * the user program continues.
+ *
+ * @return the current heading, in degrees. Or MICROBIT_CALIBRATION_IN_PROGRESS if the compass is calibrating.
  *
  * Example:
  * @code
@@ -147,7 +147,7 @@ int MicroBitCompass::heading()
     float bearing;
 
     if(status & MICROBIT_COMPASS_STATUS_CALIBRATING)
-        return MICROBIT_CALIBRATION_IN_PROGRESS;    
+        return MICROBIT_CALIBRATION_IN_PROGRESS;
 
     if(!(status & MICROBIT_COMPASS_STATUS_CALIBRATED))
         calibrate();
@@ -165,11 +165,11 @@ int MicroBitCompass::heading()
     float sinTheta = sin(theta);
     float cosTheta = cos(theta);
 
-    bearing = (360*atan2(z*sinPhi - y*cosPhi, x*cosTheta + y*sinTheta*sinPhi + z*sinTheta*cosPhi)) / (2*PI); 
+    bearing = (360*atan2(z*sinPhi - y*cosPhi, x*cosTheta + y*sinTheta*sinPhi + z*sinTheta*cosPhi)) / (2*PI);
 
     if (bearing < 0)
         bearing += 360.0;
-      
+
     return (int) bearing;
 }
 
@@ -179,7 +179,7 @@ int MicroBitCompass::heading()
   */
 void MicroBitCompass::idleTick()
 {
-    // Poll interrupt line from accelerometer (Active HI). 
+    // Poll interrupt line from accelerometer (Active HI).
     // Interrupt is cleared on data read of MAG_OUT_X_MSB.
     if(int1)
     {
@@ -225,7 +225,7 @@ int MicroBitCompass::getX(MicroBitCoordinateSystem system)
   * @code
   * uBit.compass.getY();
   * @endcode
-  */     
+  */
 int MicroBitCompass::getY(MicroBitCoordinateSystem system)
 {
     switch (system)
@@ -235,7 +235,7 @@ int MicroBitCompass::getY(MicroBitCoordinateSystem system)
 
         case NORTH_EAST_DOWN:
             return (sample.x - average.x);
-                
+
         case RAW:
         default:
             return sample.y;
@@ -250,7 +250,7 @@ int MicroBitCompass::getY(MicroBitCoordinateSystem system)
   * @code
   * uBit.compass.getZ();
   * @endcode
-  */     
+  */
 int MicroBitCompass::getZ(MicroBitCoordinateSystem system)
 {
     switch (system)
@@ -273,7 +273,7 @@ int MicroBitCompass::getZ(MicroBitCoordinateSystem system)
   * @code
   * uBit.compass.getFieldStrength();
   * @endcode
-  */     
+  */
 int MicroBitCompass::getFieldStrength()
 {
     double x = getX();
@@ -300,7 +300,7 @@ int MicroBitCompass::configure()
     if (result != MICROBIT_OK)
         return MICROBIT_I2C_ERROR;
 
-    // Wait for the part to enter standby mode...    
+    // Wait for the part to enter standby mode...
     while(1)
     {
         // Read the status of the part...
@@ -335,7 +335,7 @@ int MicroBitCompass::configure()
     if (result != MICROBIT_OK)
         return MICROBIT_I2C_ERROR;
 
-    
+
     // Bring the device online, with the requested sample frequency.
     result = writeCommand(MAG_CTRL_REG1, actualSampleRate->ctrl_reg1 | 0x01);
     if (result != MICROBIT_OK)
@@ -358,7 +358,7 @@ int MicroBitCompass::setPeriod(int period)
 }
 
 /**
- * Reads the currently configured sample rate of the compass. 
+ * Reads the currently configured sample rate of the compass.
  * @return The time between samples, in milliseconds.
  */
 int MicroBitCompass::getPeriod()
@@ -368,7 +368,7 @@ int MicroBitCompass::getPeriod()
 
 
 /**
-  * Attempts to determine the 8 bit ID from the magnetometer. 
+  * Attempts to determine the 8 bit ID from the magnetometer.
   * @return the id of the compass (magnetometer), or MICROBIT_I2C_ERROR if the magnetometer could not be updated.
   *
   * Example:
@@ -381,7 +381,7 @@ int MicroBitCompass::whoAmI()
     uint8_t data;
     int result;
 
-    result = readCommand(MAG_WHOAMI, &data, 1);    
+    result = readCommand(MAG_WHOAMI, &data, 1);
     if (result != MICROBIT_OK)
         return MICROBIT_I2C_ERROR;
 
@@ -389,7 +389,7 @@ int MicroBitCompass::whoAmI()
 }
 
 /**
- * Reads the current die temperature of the compass. 
+ * Reads the current die temperature of the compass.
  * @return the temperature in degrees celsius, or MICROBIT_I2C_ERROR if the magnetometer could not be updated.
  */
 int MicroBitCompass::readTemperature()
@@ -406,10 +406,10 @@ int MicroBitCompass::readTemperature()
 
 /**
   * Perform a calibration of the compass.
-  * 
+  *
   * This method will be called automatically if a user attempts to read a compass value when
   * the compass is uncalibrated. It can also be called at any time by the user.
-  * 
+  *
   * Any old calibration data is deleted.
   * The method will only return once the compass has been calibrated.
   *
@@ -453,7 +453,7 @@ int MicroBitCompass::calibrate()
 int MicroBitCompass::calibrateStart()
 {
     return calibrate();
-}   
+}
 
 /**
  * Perform the asynchronous calibration of the compass.
@@ -463,7 +463,7 @@ int MicroBitCompass::calibrateStart()
  * @note *** PLEASE USE THE calibrate() FUNCTION INSTEAD ***
  */
 void MicroBitCompass::calibrateAsync()
-{    
+{
     calibrate();
 }
 
@@ -472,20 +472,20 @@ void MicroBitCompass::calibrateAsync()
   * This will fire MICROBIT_COMPASS_EVT_CAL_END.
   *
   * @note *** THIS FUNCTION IS NOW DEPRECATED AND WILL BE REMOVED IN THE NEXT MAJOR RELEASE ***
-  */     
+  */
 void MicroBitCompass::calibrateEnd()
 {
-}    
+}
 
 
 /**
   * Configure the compass to use the given calibration data.
   * Calibration data is comprised of the perceived zero offset of each axis of the compass.
-  * After calibration this should now take into account trimming errors in the magnetometer, 
+  * After calibration this should now take into account trimming errors in the magnetometer,
   * and any "hard iron" offsets on the device.
   *
   * @param The x, y and z zero offsets to use as calibration data.
-  */     
+  */
 void MicroBitCompass::setCalibration(CompassSample calibration)
 {
     average = calibration;
@@ -496,8 +496,8 @@ void MicroBitCompass::setCalibration(CompassSample calibration)
   * Provides the calibration data currently in use by the compass.
   * More specifically, the x, y and z zero offsets of the compass.
   *
-  * @return The x, y and z xero offsets of the compass. 
-  */     
+  * @return The x, y and z xero offsets of the compass.
+  */
 CompassSample MicroBitCompass::getCalibration()
 {
     return average;
@@ -508,7 +508,7 @@ CompassSample MicroBitCompass::getCalibration()
   */
 int MicroBitCompass::isCalibrated()
 {
-    return status & MICROBIT_COMPASS_STATUS_CALIBRATED;   
+    return status & MICROBIT_COMPASS_STATUS_CALIBRATED;
 }
 
 /**
@@ -516,7 +516,7 @@ int MicroBitCompass::isCalibrated()
   */
 int MicroBitCompass::isCalibrating()
 {
-    return status & MICROBIT_COMPASS_STATUS_CALIBRATING;   
+    return status & MICROBIT_COMPASS_STATUS_CALIBRATING;
 }
 
 /**
@@ -524,7 +524,7 @@ int MicroBitCompass::isCalibrating()
   */
 void MicroBitCompass::clearCalibration()
 {
-    status &= ~MICROBIT_COMPASS_STATUS_CALIBRATED;    
+    status &= ~MICROBIT_COMPASS_STATUS_CALIBRATED;
 }
 
 /**
@@ -537,16 +537,24 @@ int MicroBitCompass::isIdleCallbackNeeded()
     return int1;
 }
 
+/**
+  * Destructor for MicroBitMessageBus, so that we deregister ourselves as an idleComponent
+  */
+MicroBitCompass::~MicroBitCompass()
+{
+    uBit.removeIdleComponent(this);
+}
+
 const MAG3110SampleRateConfig MAG3110SampleRate[MAG3110_SAMPLE_RATES] = {
     {12500,      0x00},        // 80 Hz
     {25000,      0x20},        // 40 Hz
-    {50000,      0x40},        // 20 Hz  
-    {100000,     0x60},        // 10 hz 
-    {200000,     0x80},        // 5 hz 
-    {400000,     0x88},        // 2.5 hz 
-    {800000,     0x90},        // 1.25 hz 
-    {1600000,    0xb0},        // 0.63 hz 
-    {3200000,    0xd0},        // 0.31 hz 
-    {6400000,    0xf0},        // 0.16 hz 
-    {12800000,   0xf8}         // 0.08 hz 
+    {50000,      0x40},        // 20 Hz
+    {100000,     0x60},        // 10 hz
+    {200000,     0x80},        // 5 hz
+    {400000,     0x88},        // 2.5 hz
+    {800000,     0x90},        // 1.25 hz
+    {1600000,    0xb0},        // 0.63 hz
+    {3200000,    0xd0},        // 0.31 hz
+    {6400000,    0xf0},        // 0.16 hz
+    {12800000,   0xf8}         // 0.08 hz
 };
diff --git a/source/MicroBitDisplay.cpp b/source/MicroBitDisplay.cpp
index 1513c10..1ad22d2 100644
--- a/source/MicroBitDisplay.cpp
+++ b/source/MicroBitDisplay.cpp
@@ -17,19 +17,19 @@ const float timings[MICROBIT_DISPLAY_GREYSCALE_BIT_DEPTH] = {0.000010, 0.000047,
   *
   * @param x the width of the display in pixels.
   * @param y the height of the display in pixels.
-  * 
+  *
   * Example:
-  * @code 
+  * @code
   * MicroBitDisplay display(MICROBIT_ID_DISPLAY, 5, 5),
   * @endcode
   */
-MicroBitDisplay::MicroBitDisplay(uint16_t id, uint8_t x, uint8_t y) : 
+MicroBitDisplay::MicroBitDisplay(uint16_t id, uint8_t x, uint8_t y) :
     font(),
     image(x*2,y)
 {
     //set pins as output
     nrf_gpio_range_cfg_output(MICROBIT_DISPLAY_COLUMN_START,MICROBIT_DISPLAY_COLUMN_START + MICROBIT_DISPLAY_COLUMN_COUNT + MICROBIT_DISPLAY_ROW_COUNT);
-    
+
     this->id = id;
     this->width = x;
     this->height = y;
@@ -38,46 +38,46 @@ MicroBitDisplay::MicroBitDisplay(uint16_t id, uint8_t x, uint8_t y) :
     this->rotation = MICROBIT_DISPLAY_ROTATION_0;
     this->greyscaleBitMsk = 0x01;
     this->timingCount = 0;
-    
+
     this->setBrightness(MICROBIT_DISPLAY_DEFAULT_BRIGHTNESS);
 
     this->mode = DISPLAY_MODE_BLACK_AND_WHITE;
     this->animationMode = ANIMATION_MODE_NONE;
-    
+
     uBit.flags |= MICROBIT_FLAG_DISPLAY_RUNNING;
 }
 
 /**
   * Internal frame update method, used to strobe the display.
   *
-  * TODO: Write a more efficient, complementary variation of this method for the case where 
+  * TODO: Write a more efficient, complementary variation of this method for the case where
   * MICROBIT_DISPLAY_ROW_COUNT > MICROBIT_DISPLAY_COLUMN_COUNT.
-  */   
+  */
 void MicroBitDisplay::systemTick()
-{   
+{
     if(!(uBit.flags & MICROBIT_FLAG_DISPLAY_RUNNING))
         return;
-        
-    // Move on to the next row. 
+
+    // Move on to the next row.
     strobeBitMsk <<= 1;
     strobeRow++;
-        
+
     //reset the row counts and bit mask when we have hit the max.
     if(strobeRow == MICROBIT_DISPLAY_ROW_COUNT){
         strobeRow = 0;
-        strobeBitMsk = 0x20;   
+        strobeBitMsk = 0x20;
     }
-      
+
     if(mode == DISPLAY_MODE_BLACK_AND_WHITE)
         render();
-    
+
     if(mode == DISPLAY_MODE_GREYSCALE)
     {
         greyscaleBitMsk = 0x01;
         timingCount = 0;
         renderGreyscale();
     }
-    
+
     // Update text and image animations if we need to.
     this->animationUpdate();
 }
@@ -87,60 +87,60 @@ void MicroBitDisplay::renderFinish()
     //kept inline to reduce overhead
     //clear the old bit pattern for this row.
     //clear port 0 4-7 and retain lower 4 bits
-    nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT0, 0xF0 | (nrf_gpio_port_read(NRF_GPIO_PORT_SELECT_PORT0) & 0x0F)); 
-    
+    nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT0, 0xF0 | (nrf_gpio_port_read(NRF_GPIO_PORT_SELECT_PORT0) & 0x0F));
+
     // clear port 1 8-12 for the current row
-    nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT1, strobeBitMsk | 0x1F); 
+    nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT1, strobeBitMsk | 0x1F);
 }
 
 void MicroBitDisplay::render()
-{   
+{
     // Simple optimisation. If display is at zero brightness, there's nothign to do.
     if(brightness == 0)
         return;
 
     int coldata = 0;
-    
+
     // Calculate the bitpattern to write.
     for (int i = 0; i<MICROBIT_DISPLAY_COLUMN_COUNT; i++)
     {
         int x = matrixMap[i][strobeRow].x;
         int y = matrixMap[i][strobeRow].y;
-        int t = x;        
-        
+        int t = x;
+
         if(rotation == MICROBIT_DISPLAY_ROTATION_90)
         {
                 x = width - 1 - y;
                 y = t;
         }
-                
+
         if(rotation == MICROBIT_DISPLAY_ROTATION_180)
         {
                 x = width - 1 - x;
                 y = height - 1 - y;
         }
-                
+
         if(rotation == MICROBIT_DISPLAY_ROTATION_270)
         {
                 x = y;
                 y = height - 1 - t;
         }
-        
+
         if(image.getBitmap()[y*(width*2)+x])
             coldata |= (1 << i);
     }
-                    
+
     //write the new bit pattern
     //set port 0 4-7 and retain lower 4 bits
-    nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT0, (~coldata<<4 & 0xF0) | (nrf_gpio_port_read(NRF_GPIO_PORT_SELECT_PORT0) & 0x0F)); 
-    
+    nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT0, (~coldata<<4 & 0xF0) | (nrf_gpio_port_read(NRF_GPIO_PORT_SELECT_PORT0) & 0x0F));
+
     //set port 1 8-12 for the current row
-    nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT1, strobeBitMsk | (~coldata>>4 & 0x1F)); 
+    nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT1, strobeBitMsk | (~coldata>>4 & 0x1F));
 
     //timer does not have enough resolution for brightness of 1. 23.53 us
     if(brightness != MICROBIT_DISPLAY_MAXIMUM_BRIGHTNESS && brightness > MICROBIT_DISPLAY_MINIMUM_BRIGHTNESS)
         renderTimer.attach(this, &MicroBitDisplay::renderFinish, (((float)brightness) / ((float)MICROBIT_DISPLAY_MAXIMUM_BRIGHTNESS)) * (float)MICROBIT_DISPLAY_REFRESH_PERIOD);
-    
+
     //this will take around 23us to execute
     if(brightness <= MICROBIT_DISPLAY_MINIMUM_BRIGHTNESS)
         renderFinish();
@@ -149,47 +149,47 @@ void MicroBitDisplay::render()
 void MicroBitDisplay::renderGreyscale()
 {
     int coldata = 0;
-    
+
     // Calculate the bitpattern to write.
     for (int i = 0; i<MICROBIT_DISPLAY_COLUMN_COUNT; i++)
     {
         int x = matrixMap[i][strobeRow].x;
         int y = matrixMap[i][strobeRow].y;
-        int t = x;        
-        
+        int t = x;
+
         if(rotation == MICROBIT_DISPLAY_ROTATION_90)
         {
                 x = width - 1 - y;
                 y = t;
         }
-                
+
         if(rotation == MICROBIT_DISPLAY_ROTATION_180)
         {
                 x = width - 1 - x;
                 y = height - 1 - y;
         }
-                
+
         if(rotation == MICROBIT_DISPLAY_ROTATION_270)
         {
                 x = y;
                 y = height - 1 - t;
         }
-        
+
         if(min(image.getBitmap()[y * (width * 2) + x],brightness) & greyscaleBitMsk)
             coldata |= (1 << i);
-    }            
+    }
     //write the new bit pattern
     //set port 0 4-7 and retain lower 4 bits
-    nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT0, (~coldata<<4 & 0xF0) | (nrf_gpio_port_read(NRF_GPIO_PORT_SELECT_PORT0) & 0x0F)); 
-    
+    nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT0, (~coldata<<4 & 0xF0) | (nrf_gpio_port_read(NRF_GPIO_PORT_SELECT_PORT0) & 0x0F));
+
     //set port 1 8-12 for the current row
-    nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT1, strobeBitMsk | (~coldata>>4 & 0x1F)); 
+    nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT1, strobeBitMsk | (~coldata>>4 & 0x1F));
 
     if(timingCount > MICROBIT_DISPLAY_GREYSCALE_BIT_DEPTH-1)
         return;
 
     greyscaleBitMsk <<= 1;
-    
+
     renderTimer.attach(this,&MicroBitDisplay::renderGreyscale, timings[timingCount++]);
 }
 
@@ -198,29 +198,29 @@ void MicroBitDisplay::renderGreyscale()
   */
 void
 MicroBitDisplay::animationUpdate()
-{   
+{
     // If there's no ongoing animation, then nothing to do.
     if (animationMode == ANIMATION_MODE_NONE)
         return;
-    
-    animationTick += FIBER_TICK_PERIOD_MS; 
-    
+
+    animationTick += FIBER_TICK_PERIOD_MS;
+
     if(animationTick >= animationDelay)
     {
         animationTick = 0;
-        
+
         if (animationMode == ANIMATION_MODE_SCROLL_TEXT)
             this->updateScrollText();
-        
+
         if (animationMode == ANIMATION_MODE_PRINT_TEXT)
             this->updatePrintText();
 
         if (animationMode == ANIMATION_MODE_SCROLL_IMAGE)
             this->updateScrollImage();
-            
+
         if (animationMode == ANIMATION_MODE_ANIMATE_IMAGE)
             this->updateAnimateImage();
-            
+
         if(animationMode == ANIMATION_MODE_PRINT_CHARACTER)
         {
             animationMode = ANIMATION_MODE_NONE;
@@ -243,18 +243,18 @@ void MicroBitDisplay::sendAnimationCompleteEvent()
 }
 
 /**
-  * Internal scrollText update method. 
+  * Internal scrollText update method.
   * Shift the screen image by one pixel to the left. If necessary, paste in the next char.
-  */   
+  */
 void MicroBitDisplay::updateScrollText()
-{    
+{
     image.shiftLeft(1);
     scrollingPosition++;
-    
+
     if (scrollingPosition == width + MICROBIT_DISPLAY_SPACING)
-    {        
+    {
         scrollingPosition = 0;
-        
+
         image.print(scrollingChar < scrollingText.length() ? scrollingText.charAt(scrollingChar) : ' ',width,0);
 
         if (scrollingChar > scrollingText.length())
@@ -268,36 +268,36 @@ void MicroBitDisplay::updateScrollText()
 }
 
 /**
-  * Internal printText update method. 
+  * Internal printText update method.
   * Paste in the next char in the string.
-  */   
+  */
 void MicroBitDisplay::updatePrintText()
-{        
+{
     image.print(printingChar < printingText.length() ? printingText.charAt(printingChar) : ' ',0,0);
 
     if (printingChar > printingText.length())
     {
-        animationMode = ANIMATION_MODE_NONE;   
+        animationMode = ANIMATION_MODE_NONE;
 
         this->sendAnimationCompleteEvent();
         return;
     }
-    
+
     printingChar++;
 }
 
 /**
-  * Internal scrollImage update method. 
+  * Internal scrollImage update method.
   * Paste the stored bitmap at the appropriate point.
-  */   
+  */
 void MicroBitDisplay::updateScrollImage()
-{   
-    image.clear();     
+{
+    image.clear();
 
-    if ((image.paste(scrollingImage, scrollingImagePosition, 0, 0) == 0) && scrollingImageRendered)
+    if (((image.paste(scrollingImage, scrollingImagePosition, 0, 0) == 0) && scrollingImageRendered) || scrollingImageStride == 0)
     {
-        animationMode = ANIMATION_MODE_NONE;  
-        this->sendAnimationCompleteEvent();     
+        animationMode = ANIMATION_MODE_NONE;
+        this->sendAnimationCompleteEvent();
 
         return;
     }
@@ -307,27 +307,33 @@ void MicroBitDisplay::updateScrollImage()
 }
 
 /**
-  * Internal animateImage update method. 
+  * Internal animateImage update method.
   * Paste the stored bitmap at the appropriate point and stop on the last frame.
-  */   
+  */
 void MicroBitDisplay::updateAnimateImage()
-{   
+{
     //wait until we have rendered the last position to give a continuous animation.
     if (scrollingImagePosition <= -scrollingImage.getWidth() + (MICROBIT_DISPLAY_WIDTH + scrollingImageStride) && scrollingImageRendered)
     {
-        animationMode = ANIMATION_MODE_NONE;  
+        animationMode = ANIMATION_MODE_NONE;
         this->clear();
-        this->sendAnimationCompleteEvent();     
+        this->sendAnimationCompleteEvent();
         return;
     }
-    
+
     if(scrollingImagePosition > 0)
         image.shiftLeft(-scrollingImageStride);
-        
+
     image.paste(scrollingImage, scrollingImagePosition, 0, 0);
-        
+
+    if(scrollingImageStride == 0)
+    {
+        animationMode = ANIMATION_MODE_NONE;
+        this->sendAnimationCompleteEvent();
+    }
+
     scrollingImageRendered = true;
-        
+
     scrollingImagePosition += scrollingImageStride;
 }
 
@@ -347,7 +353,7 @@ void MicroBitDisplay::stopAnimation()
         // Wake up aall fibers that may blocked on the animation (if any).
         MicroBitEvent(MICROBIT_ID_NOTIFY, MICROBIT_DISPLAY_EVT_FREE);
     }
-    
+
     // Clear the display and setup the animation timers.
     this->image.clear();
 }
@@ -356,7 +362,7 @@ void MicroBitDisplay::stopAnimation()
   * Blocks the current fiber until the display is available (i.e. not effect is being displayed).
   * Animations are queued until their time to display.
   *
-  */ 
+  */
 void MicroBitDisplay::waitForFreeDisplay()
 {
     // If there's an ongoing animation, wait for our turn to display.
@@ -371,9 +377,9 @@ void MicroBitDisplay::waitForFreeDisplay()
   * @param c The character to display.
   * @param delay Optional parameter - the time for which to show the character. Zero displays the character forever.
   * @return MICROBIT_OK, MICROBIT_BUSY is the screen is in use, or MICROBIT_INVALID_PARAMETER.
-  * 
+  *
   * Example:
-  * @code 
+  * @code
   * uBit.display.printAsync('p');
   * uBit.display.printAsync('p',100);
   * @endcode
@@ -422,7 +428,7 @@ int MicroBitDisplay::printAsync(ManagedString s, int delay)
     //sanitise this value
     if(delay <= 0 )
         return MICROBIT_INVALID_PARAMETER;
-    
+
     if (animationMode == ANIMATION_MODE_NONE || animationMode == ANIMATION_MODE_STOPPED)
     {
         printingChar = 0;
@@ -431,7 +437,7 @@ int MicroBitDisplay::printAsync(ManagedString s, int delay)
         animationTick = 0;
 
         animationMode = ANIMATION_MODE_PRINT_TEXT;
-    } 
+    }
     else
     {
         return MICROBIT_BUSY;
@@ -448,7 +454,7 @@ int MicroBitDisplay::printAsync(ManagedString s, int delay)
   * @param i The image to display.
   * @param x The horizontal position on the screen to display the image (default 0)
   * @param y The vertical position on the screen to display the image (default 0)
-  * @param alpha Treats the brightness level '0' as transparent (default 0) 
+  * @param alpha Treats the brightness level '0' as transparent (default 0)
   * @param delay The time to delay between characters, in milliseconds. set to 0 to display forever. (default 0).
   *
   * Example:
@@ -487,9 +493,9 @@ int MicroBitDisplay::printAsync(MicroBitImage i, int x, int y, int alpha, int de
   * @param c The character to display.
   * @param delay The time to delay between characters, in milliseconds. Must be > 0.
   * @return MICROBIT_OK, MICROBIT_CANCELLED or MICROBIT_INVALID_PARAMETER.
-  * 
+  *
   * Example:
-  * @code 
+  * @code
   * uBit.display.print('p');
   * uBit.display.print('p',100);
   * @endcode
@@ -537,7 +543,7 @@ int MicroBitDisplay::print(ManagedString s, int delay)
     //sanitise this value
     if(delay <= 0 )
         return MICROBIT_INVALID_PARAMETER;
-    
+
     // If there's an ongoing animation, wait for our turn to display.
     this->waitForFreeDisplay();
 
@@ -613,7 +619,7 @@ int MicroBitDisplay::scrollAsync(ManagedString s, int delay)
     //sanitise this value
     if(delay <= 0)
         return MICROBIT_INVALID_PARAMETER;
-    
+
     // If the display is free, it's our turn to display.
     if (animationMode == ANIMATION_MODE_NONE || animationMode == ANIMATION_MODE_STOPPED)
     {
@@ -649,7 +655,7 @@ int MicroBitDisplay::scrollAsync(ManagedString s, int delay)
   * @endcode
   */
 int MicroBitDisplay::scrollAsync(MicroBitImage image, int delay, int stride)
-{   
+{
     //sanitise the delay value
     if(delay <= 0)
         return MICROBIT_INVALID_PARAMETER;
@@ -662,7 +668,7 @@ int MicroBitDisplay::scrollAsync(MicroBitImage image, int delay, int stride)
         scrollingImage = image;
         scrollingImageRendered = false;
 
-        animationDelay = delay;
+        animationDelay = stride == 0 ? 0 : delay;
         animationTick = 0;
         animationMode = ANIMATION_MODE_SCROLL_IMAGE;
     }
@@ -682,9 +688,9 @@ int MicroBitDisplay::scrollAsync(MicroBitImage image, int delay, int stride)
   * @param s The string to display.
   * @param delay The time to delay between each update to the display, in milliseconds. Must be > 0.
   * @return MICROBIT_OK, MICROBIT_CANCELLED or MICROBIT_INVALID_PARAMETER.
-  * 
+  *
   * Example:
-  * @code 
+  * @code
   * uBit.display.scrollString("abc123",100);
   * @endcode
   */
@@ -706,12 +712,12 @@ int MicroBitDisplay::scroll(ManagedString s, int delay)
 
         // Wait for completion.
         fiber_wait_for_event(MICROBIT_ID_DISPLAY, MICROBIT_DISPLAY_EVT_ANIMATION_COMPLETE);
-    } 
+    }
     else
     {
         return MICROBIT_CANCELLED;
     }
-    
+
     return MICROBIT_OK;
 }
 
@@ -731,11 +737,11 @@ int MicroBitDisplay::scroll(ManagedString s, int delay)
   * @endcode
   */
 int MicroBitDisplay::scroll(MicroBitImage image, int delay, int stride)
-{   
+{
     //sanitise the delay value
     if(delay <= 0)
         return MICROBIT_INVALID_PARAMETER;
-    
+
     // If there's an ongoing animation, wait for our turn to display.
     this->waitForFreeDisplay();
 
@@ -789,12 +795,12 @@ int MicroBitDisplay::animateAsync(MicroBitImage image, int delay, int stride, in
         stride = -stride;
 
         //calculate starting position which is offset by the stride
-        scrollingImagePosition = (startingPosition == MICROBIT_DISPLAY_ANIMATE_DEFAULT_POS) ? MICROBIT_DISPLAY_WIDTH + stride : startingPosition; 
+        scrollingImagePosition = (startingPosition == MICROBIT_DISPLAY_ANIMATE_DEFAULT_POS) ? MICROBIT_DISPLAY_WIDTH + stride : startingPosition;
         scrollingImageStride = stride;
         scrollingImage = image;
         scrollingImageRendered = false;
 
-        animationDelay = delay;
+        animationDelay = stride == 0 ? 0 : delay;
         animationTick = delay-1;
         animationMode = ANIMATION_MODE_ANIMATE_IMAGE;
     }
@@ -858,14 +864,14 @@ int MicroBitDisplay::animate(MicroBitImage image, int delay, int stride, int sta
   * Sets the display brightness to the specified level.
   * @param b The brightness to set the brightness to, in the range 0..255.
   * @return MICROBIT_OK, or MICROBIT_INVALID_PARAMETER
-  * 
+  *
   * Example:
-  * @code 
+  * @code
   * uBit.display.setBrightness(255); //max brightness
   * @endcode
-  */  
+  */
 int MicroBitDisplay::setBrightness(int b)
-{  
+{
     //sanitise the brightness level
     if(b < 0 || b > 255)
         return MICROBIT_INVALID_PARAMETER;
@@ -878,26 +884,26 @@ int MicroBitDisplay::setBrightness(int b)
 /**
   * Sets the mode of the display.
   * @param mode The mode to swap the display into. (can be either DISPLAY_MODE_GREYSCALE, or DISPLAY_MODE_NORMAL)
-  * 
+  *
   * Example:
-  * @code 
+  * @code
   * uBit.display.setDisplayMode(DISPLAY_MODE_GREYSCALE); //per pixel brightness
   * @endcode
-  */  
+  */
 void MicroBitDisplay::setDisplayMode(DisplayMode mode)
-{   
+{
     this->mode = mode;
 }
 
 /**
   * Fetches the current brightness of this display.
   * @return the brightness of this display, in the range 0..255.
-  * 
+  *
   * Example:
-  * @code 
+  * @code
   * uBit.display.getBrightness(); //the current brightness
   * @endcode
-  */  
+  */
 int MicroBitDisplay::getBrightness()
 {
     return this->brightness;
@@ -908,10 +914,10 @@ int MicroBitDisplay::getBrightness()
   * Axis aligned values only.
   *
   * Example:
-  * @code 
+  * @code
   * uBit.display.rotateTo(MICROBIT_DISPLAY_ROTATION_180); //rotates 180 degrees from original orientation
   * @endcode
-  */   
+  */
 void MicroBitDisplay::rotateTo(DisplayRotation rotation)
 {
     this->rotation = rotation;
@@ -921,7 +927,7 @@ void MicroBitDisplay::rotateTo(DisplayRotation rotation)
   * Enables the display, should only be called if the display is disabled.
   *
   * Example:
-  * @code 
+  * @code
   * uBit.display.enable(); //reenables the display mechanics
   * @endcode
   */
@@ -933,13 +939,13 @@ void MicroBitDisplay::enable()
         uBit.flags |= MICROBIT_FLAG_DISPLAY_RUNNING;            //set the display running flag
     }
 }
-    
+
 /**
   * Disables the display, should only be called if the display is enabled.
   * Display must be disabled to avoid MUXing of edge connector pins.
   *
   * Example:
-  * @code 
+  * @code
   * uBit.display.disable(); //disables the display
   * @endcode
   */
@@ -948,7 +954,7 @@ void MicroBitDisplay::disable()
     if(uBit.flags & MICROBIT_FLAG_DISPLAY_RUNNING)
     {
         uBit.flags &= ~MICROBIT_FLAG_DISPLAY_RUNNING;           //unset the display running flag
-    }   
+    }
 }
 
 /**
@@ -956,13 +962,13 @@ void MicroBitDisplay::disable()
   * Simplifies the process, you can also use uBit.display.image.clear
   *
   * Example:
-  * @code 
+  * @code
   * uBit.display.clear(); //clears the display
   * @endcode
-  */ 
+  */
 void MicroBitDisplay::clear()
 {
-    image.clear();  
+    image.clear();
 }
 
 /**
@@ -970,12 +976,12 @@ void MicroBitDisplay::clear()
   * @param statusCode the appropriate status code - 0 means no code will be displayed. Status codes must be in the range 0-255.
   *
   * Example:
-  * @code 
+  * @code
   * uBit.display.error(20);
   * @endcode
   */
 void MicroBitDisplay::error(int statusCode)
-{   
+{
     extern InterruptIn resetButton;
 
     __disable_irq(); //stop ALL interrupts
@@ -984,16 +990,16 @@ void MicroBitDisplay::error(int statusCode)
         statusCode = 0;
 
     disable(); //relinquish PWMOut's control
-    
+
     uint8_t strobeRow = 0;
     uint8_t strobeBitMsk = 0x20;
-    
+
     //point to the font stored in Flash
     const unsigned char * fontLocation = MicroBitFont::defaultFont;
-    
+
     //get individual digits of status code, and place it into a single array/
     const uint8_t* chars[MICROBIT_DISPLAY_ERROR_CHARS] = { panicFace, fontLocation+((((statusCode/100 % 10)+48)-MICROBIT_FONT_ASCII_START) * 5), fontLocation+((((statusCode/10 % 10)+48)-MICROBIT_FONT_ASCII_START) * 5), fontLocation+((((statusCode % 10)+48)-MICROBIT_FONT_ASCII_START) * 5)};
-    
+
     //enter infinite loop.
     while(1)
     {
@@ -1001,42 +1007,42 @@ void MicroBitDisplay::error(int statusCode)
         for(int characterCount = 0; characterCount < MICROBIT_DISPLAY_ERROR_CHARS; characterCount++)
         {
             int outerCount = 0;
-            
+
             //display the current character
             while(outerCount < 500)
             {
                 int coldata = 0;
-        
+
                 int i = 0;
-        
+
                 //if we have hit the row limit - reset both the bit mask and the row variable
                 if(strobeRow == 3)
                 {
-                    strobeRow = 0; 
+                    strobeRow = 0;
                     strobeBitMsk = 0x20;
-                }    
-        
+                }
+
                 // Calculate the bitpattern to write.
                 for (i = 0; i<MICROBIT_DISPLAY_COLUMN_COUNT; i++)
                 {
-                    
+
                     int bitMsk = 0x10 >> matrixMap[i][strobeRow].x; //chars are right aligned but read left to right
                     int y = matrixMap[i][strobeRow].y;
-                         
+
                     if(chars[characterCount][y] & bitMsk)
                         coldata |= (1 << i);
                 }
-                
+
                 nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT0, 0xF0); //clear port 0 4-7
                 nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT1, strobeBitMsk | 0x1F); // clear port 1 8-12
-                
+
                 //write the new bit pattern
                 nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT0, ~coldata<<4 & 0xF0); //set port 0 4-7
                 nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT1, strobeBitMsk | (~coldata>>4 & 0x1F)); //set port 1 8-12
-            
+
                 //set i to an obscene number.
                 i = 1000;
-                
+
                 //burn cycles
                 while(i>0)
                 {
@@ -1046,9 +1052,9 @@ void MicroBitDisplay::error(int statusCode)
 
                     i--;
                 }
-                
+
                 //update the bit mask and row count
-                strobeBitMsk <<= 1;    
+                strobeBitMsk <<= 1;
                 strobeRow++;
                 outerCount++;
             }
@@ -1080,3 +1086,11 @@ MicroBitImage MicroBitDisplay::screenShot()
 {
     return image.crop(0,0,MICROBIT_DISPLAY_WIDTH,MICROBIT_DISPLAY_HEIGHT);
 }
+
+/**
+  * Destructor for MicroBitDisplay, so that we deregister ourselves as a systemComponent
+  */
+MicroBitDisplay::~MicroBitDisplay()
+{
+    uBit.removeSystemComponent(this);
+}
diff --git a/source/MicroBitMessageBus.cpp b/source/MicroBitMessageBus.cpp
index bf85e52..7fcd28d 100644
--- a/source/MicroBitMessageBus.cpp
+++ b/source/MicroBitMessageBus.cpp
@@ -7,7 +7,7 @@
 #include "MicroBit.h"
 
 /**
-  * Constructor. 
+  * Constructor.
   * Create a new Message Bus.
   */
 MicroBitMessageBus::MicroBitMessageBus()
@@ -30,7 +30,7 @@ void async_callback(void *param)
 
     // OK, now we need to decide how to behave depending on our configuration.
     // If this a fiber f already active within this listener then check our
-    // configuration to determine the correct course of action. 
+    // configuration to determine the correct course of action.
     //
 
     if (listener->flags & MESSAGE_BUS_LISTENER_BUSY)
@@ -47,7 +47,7 @@ void async_callback(void *param)
         }
     }
 
-    // Determine the calling convention for the callback, and invoke... 
+    // Determine the calling convention for the callback, and invoke...
     // C++ is really bad at this! Especially as the ARM compiler is yet to support C++ 11 :-/
 
     // Record that we have a fiber going into this listener...
@@ -91,7 +91,7 @@ void async_callback(void *param)
   * Queue the given event for processing at a later time.
   * Add the given event at the tail of our queue.
   *
-  * @param The event to queue. 
+  * @param The event to queue.
   */
 void MicroBitMessageBus::queueEvent(MicroBitEvent &evt)
 {
@@ -99,7 +99,7 @@ void MicroBitMessageBus::queueEvent(MicroBitEvent &evt)
 
     MicroBitEventQueueItem *prev = evt_queue_tail;
 
-    // Now process all handler regsitered as URGENT. 
+    // Now process all handler regsitered as URGENT.
     // These pre-empt the queue, and are useful for fast, high priority services.
     processingComplete = this->process(evt, true);
 
@@ -125,7 +125,7 @@ void MicroBitMessageBus::queueEvent(MicroBitEvent &evt)
     {
         item->next = evt_queue_head;
         evt_queue_head = item;
-    } 
+    }
     else
     {
         item->next = prev->next;
@@ -142,18 +142,18 @@ void MicroBitMessageBus::queueEvent(MicroBitEvent &evt)
 
 /**
   * Extract the next event from the front of the event queue (if present).
-  * @return 
+  * @return
   *
-  * @param The event to queue. 
+  * @param The event to queue.
   */
 MicroBitEventQueueItem* MicroBitMessageBus::dequeueEvent()
 {
     MicroBitEventQueueItem *item = NULL;
 
     __disable_irq();
- 
+
     if (evt_queue_head != NULL)
-    { 
+    {
         item = evt_queue_head;
         evt_queue_head = item->next;
 
@@ -162,7 +162,7 @@ MicroBitEventQueueItem* MicroBitMessageBus::dequeueEvent()
 
         queueLength--;
     }
-    
+
     __enable_irq();
 
 
@@ -188,7 +188,7 @@ int MicroBitMessageBus::deleteMarkedListeners()
         {
             if (p == NULL)
                 listeners = l->next;
-            else 
+            else
                 p->next = l->next;
 
             // delete the listener.
@@ -212,7 +212,7 @@ int MicroBitMessageBus::deleteMarkedListeners()
   * Periodic callback from MicroBit.
   * Process at least one event from the event queue, if it is not empty.
   * We then continue processing events until something appears on the runqueue.
-  */  
+  */
 void MicroBitMessageBus::idleTick()
 {
     // Clear out any listeners marked for deletion
@@ -231,7 +231,7 @@ void MicroBitMessageBus::idleTick()
 
         // If we have created some useful work to do, we stop processing.
         // This helps to minimise the number of blocked fibers we create at any point in time, therefore
-        // also reducing the RAM footprint. 
+        // also reducing the RAM footprint.
         if(!scheduler_runqueue_empty())
             break;
 
@@ -242,26 +242,26 @@ void MicroBitMessageBus::idleTick()
 
 /**
   * Indicates whether or not we have any background work to do.
-  * @ return 1 if there are any events waitingto be processed, 0 otherwise. 
+  * @ return 1 if there are any events waitingto be processed, 0 otherwise.
   */
 int MicroBitMessageBus::isIdleCallbackNeeded()
 {
-    return !(evt_queue_head == NULL);  
+    return !(evt_queue_head == NULL);
 }
 
 /**
   * Queues the given event to be sent to all registered recipients.
   *
-  * @param The event to send. 
+  * @param The event to send.
   *
   * n.b. THIS IS NOW WRAPPED BY THE MicroBitEvent CLASS FOR CONVENIENCE...
   *
   * Example:
-  * @code 
+  * @code
   * MicroBitEvent evt(id,MICROBIT_BUTTON_EVT_DOWN,ticks,CREATE_ONLY);
   * evt.fire();
   *
-  * //OR YOU CAN DO THIS...  
+  * //OR YOU CAN DO THIS...
   * MicroBitEvent evt(id,MICROBIT_BUTTON_EVT_DOWN);
   * @endcode
   */
@@ -299,7 +299,7 @@ int MicroBitMessageBus::process(MicroBitEvent &evt, bool urgent)
             {
                 l->evt = evt;
 
-                // OK, if this handler has regisitered itself as non-blocking, we just execute it directly... 
+                // OK, if this handler has regisitered itself as non-blocking, we just execute it directly...
                 // This is normally only done for trusted system components.
                 // Otherwise, we invoke it in a 'fork on block' context, that will automatically create a fiber
                 // should the event handler attempt a blocking operation, but doesn't have the overhead
@@ -323,11 +323,11 @@ int MicroBitMessageBus::process(MicroBitEvent &evt, bool urgent)
 
 /**
   * Register a listener function.
-  * 
-  * @param id The source of messages to listen for. Events sent from any other IDs will be filtered. 
+  *
+  * @param id The source of messages to listen for. Events sent from any other IDs will be filtered.
   * Use MICROBIT_ID_ANY to receive events from all components.
   *
-  * @param value The value of messages to listen for. Events with any other values will be filtered. 
+  * @param value The value of messages to listen for. Events with any other values will be filtered.
   * Use MICROBIT_VALUE_ANY to receive events of any value.
   *
   * @param handler The function to call when an event is received.
@@ -335,7 +335,7 @@ int MicroBitMessageBus::process(MicroBitEvent &evt, bool urgent)
   * @return MICROBIT_OK on success MICROBIT_INVALID_PARAMETER
   *
   * Example:
-  * @code 
+  * @code
   * void onButtonBClick(MicroBitEvent evt)
   * {
   * 	//do something
@@ -344,7 +344,7 @@ int MicroBitMessageBus::process(MicroBitEvent &evt, bool urgent)
   * @endcode
   */
 
-int MicroBitMessageBus::listen(int id, int value, void (*handler)(MicroBitEvent), uint16_t flags) 
+int MicroBitMessageBus::listen(int id, int value, void (*handler)(MicroBitEvent), uint16_t flags)
 {
 	if (handler == NULL)
 		return MICROBIT_INVALID_PARAMETER;
@@ -360,7 +360,7 @@ int MicroBitMessageBus::listen(int id, int value, void (*handler)(MicroBitEvent)
 
 }
 
-int MicroBitMessageBus::listen(int id, int value, void (*handler)(MicroBitEvent, void*), void* arg, uint16_t flags) 
+int MicroBitMessageBus::listen(int id, int value, void (*handler)(MicroBitEvent, void*), void* arg, uint16_t flags)
 {
 	if (handler == NULL)
 		return MICROBIT_INVALID_PARAMETER;
@@ -378,20 +378,20 @@ int MicroBitMessageBus::listen(int id, int value, void (*handler)(MicroBitEvent,
 /**
  * Unregister a listener function.
  * Listners are identified by the Event ID, Event VALUE and handler registered using listen().
- * 
+ *
  * @param id The Event ID used to register the listener.
  * @param value The Event VALUE used to register the listener.
  * @param handler The function used to register the listener.
  *
  *
  * Example:
- * @code 
+ * @code
  * void onButtonBClick()
  * {
  * 	//do something
  * }
  *
- * uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, onButtonBClick); 
+ * uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, onButtonBClick);
  * @endcode
  */
 int MicroBitMessageBus::ignore(int id, int value, void (*handler)(MicroBitEvent))
@@ -408,20 +408,20 @@ int MicroBitMessageBus::ignore(int id, int value, void (*handler)(MicroBitEvent)
 /**
  * Unregister a listener function.
  * Listners are identified by the Event ID, Event VALUE and handler registered using listen().
- * 
+ *
  * @param id The Event ID used to register the listener.
  * @param value The Event VALUE used to register the listener.
  * @param handler The function used to register the listener.
  *
  *
  * Example:
- * @code 
+ * @code
  * void onButtonBClick(void *arg)
  * {
  * 	//do something
  * }
  *
- * uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, onButtonBClick); 
+ * uBit.MessageBus.ignore(MICROBIT_ID_BUTTON_B, MICROBIT_BUTTON_EVT_CLICK, onButtonBClick);
  * @endcode
  */
 int MicroBitMessageBus::ignore(int id, int value, void (*handler)(MicroBitEvent, void*))
@@ -464,7 +464,7 @@ int MicroBitMessageBus::add(MicroBitListener *newListener)
 
         if (l->id == newListener->id && l->value == newListener->value && (methodCallback ? *l->cb_method == *newListener->cb_method : l->cb == newListener->cb))
         {
-            // We have a perfect match for this event listener already registered. 
+            // We have a perfect match for this event listener already registered.
             // If it's marked for deletion, we simply resurrect the listener, and we're done.
             // Either way, we return an error code, as the *new* listener should be released...
             if(l->flags & MESSAGE_BUS_LISTENER_DELETING)
@@ -484,7 +484,7 @@ int MicroBitMessageBus::add(MicroBitListener *newListener)
 		return MICROBIT_OK;
 	}
 
-	// We maintain an ordered list of listeners. 
+	// We maintain an ordered list of listeners.
 	// The chain is held stictly in increasing order of ID (first level), then value code (second level).
 	// Find the correct point in the chain for this event.
 	// Adding a listener is a rare occurance, so we just walk the list...
@@ -544,7 +544,7 @@ int MicroBitMessageBus::remove(MicroBitListener *listener)
     {
         if ((listener->flags & MESSAGE_BUS_LISTENER_METHOD) == (l->flags & MESSAGE_BUS_LISTENER_METHOD))
         {
-            if(((listener->flags & MESSAGE_BUS_LISTENER_METHOD) && (*l->cb_method == *listener->cb_method)) || 
+            if(((listener->flags & MESSAGE_BUS_LISTENER_METHOD) && (*l->cb_method == *listener->cb_method)) ||
               ((!(listener->flags & MESSAGE_BUS_LISTENER_METHOD) && l->cb == listener->cb)))
             {
                 if ((listener->id == MICROBIT_ID_ANY || listener->id == l->id) && (listener->value == MICROBIT_EVT_ANY || listener->value == l->value))
@@ -586,3 +586,10 @@ MicroBitListener* MicroBitMessageBus::elementAt(int n)
     return l;
 }
 
+/**
+  * Destructor for MicroBitMessageBus, so that we deregister ourselves as an idleComponent
+  */
+MicroBitMessageBus::~MicroBitMessageBus()
+{
+    uBit.removeIdleComponent(this);
+}