diff --git a/java/src/com/android/inputmethod/keyboard/KeyboardSwitcher.java b/java/src/com/android/inputmethod/keyboard/KeyboardSwitcher.java
index 166be81..8880af4 100644
--- a/java/src/com/android/inputmethod/keyboard/KeyboardSwitcher.java
+++ b/java/src/com/android/inputmethod/keyboard/KeyboardSwitcher.java
@@ -314,10 +314,7 @@
                 R.layout.input_view, null);
 
         mKeyboardView = (MainKeyboardView) mCurrentInputView.findViewById(R.id.keyboard_view);
-        if (isHardwareAcceleratedDrawingEnabled) {
-            mKeyboardView.setLayerType(View.LAYER_TYPE_HARDWARE, null);
-            // TODO: Should use LAYER_TYPE_SOFTWARE when hardware acceleration is off?
-        }
+        mKeyboardView.setHardwareAcceleratedDrawingEnabled(isHardwareAcceleratedDrawingEnabled);
         mKeyboardView.setKeyboardActionListener(mLatinIME);
 
         // This always needs to be set since the accessibility state can
diff --git a/java/src/com/android/inputmethod/keyboard/KeyboardView.java b/java/src/com/android/inputmethod/keyboard/KeyboardView.java
index 2a02682..054c503 100644
--- a/java/src/com/android/inputmethod/keyboard/KeyboardView.java
+++ b/java/src/com/android/inputmethod/keyboard/KeyboardView.java
@@ -154,6 +154,12 @@
                 Color.red(color), Color.green(color), Color.blue(color));
     }
 
+    public void setHardwareAcceleratedDrawingEnabled(final boolean enabled) {
+        if (!enabled) return;
+        // TODO: Should use LAYER_TYPE_SOFTWARE when hardware acceleration is off?
+        setLayerType(LAYER_TYPE_HARDWARE, null);
+    }
+
     /**
      * Attaches a keyboard to this view. The keyboard can be switched at any time and the
      * view will re-layout itself to accommodate the keyboard.
diff --git a/java/src/com/android/inputmethod/keyboard/MainKeyboardView.java b/java/src/com/android/inputmethod/keyboard/MainKeyboardView.java
index 5334b45..6782317 100644
--- a/java/src/com/android/inputmethod/keyboard/MainKeyboardView.java
+++ b/java/src/com/android/inputmethod/keyboard/MainKeyboardView.java
@@ -512,6 +512,12 @@
         mKeyboardActionListener = KeyboardActionListener.EMPTY_LISTENER;
     }
 
+    @Override
+    public void setHardwareAcceleratedDrawingEnabled(final boolean enabled) {
+        super.setHardwareAcceleratedDrawingEnabled(enabled);
+        mPreviewPlacerView.setHardwareAcceleratedDrawingEnabled(enabled);
+    }
+
     private ObjectAnimator loadObjectAnimator(final int resId, final Object target) {
         if (resId == 0) {
             // TODO: Stop returning null.
@@ -1055,26 +1061,10 @@
             ResearchLogger.mainKeyboardView_processMotionEvent(me);
         }
 
-        final int action = me.getActionMasked();
-        final long eventTime = me.getEventTime();
-        if (action == MotionEvent.ACTION_MOVE) {
-            final int pointerCount = me.getPointerCount();
-            for (int index = 0; index < pointerCount; index++) {
-                final int id = me.getPointerId(index);
-                final PointerTracker tracker = PointerTracker.getPointerTracker(id, this);
-                final int x = (int)me.getX(index);
-                final int y = (int)me.getY(index);
-                tracker.onMoveEvent(x, y, eventTime, me);
-            }
-        } else {
-            final int index = me.getActionIndex();
-            final int id = me.getPointerId(index);
-            final int x = (int)me.getX(index);
-            final int y = (int)me.getY(index);
-            final PointerTracker tracker = PointerTracker.getPointerTracker(id, this);
-            tracker.processMotionEvent(action, x, y, eventTime, this);
-        }
-
+        final int index = me.getActionIndex();
+        final int id = me.getPointerId(index);
+        final PointerTracker tracker = PointerTracker.getPointerTracker(id, this);
+        tracker.processMotionEvent(me, this);
         return true;
     }
 
diff --git a/java/src/com/android/inputmethod/keyboard/PointerTracker.java b/java/src/com/android/inputmethod/keyboard/PointerTracker.java
index bbaf969..ab5fee9 100644
--- a/java/src/com/android/inputmethod/keyboard/PointerTracker.java
+++ b/java/src/com/android/inputmethod/keyboard/PointerTracker.java
@@ -870,8 +870,23 @@
         mListener.onCancelBatchInput();
     }
 
-    public void processMotionEvent(final int action, final int x, final int y, final long eventTime,
-            final KeyEventHandler handler) {
+    public void processMotionEvent(final MotionEvent me, final KeyEventHandler handler) {
+        final int action = me.getActionMasked();
+        final long eventTime = me.getEventTime();
+        if (action == MotionEvent.ACTION_MOVE) {
+            final int pointerCount = me.getPointerCount();
+            for (int index = 0; index < pointerCount; index++) {
+                final int id = me.getPointerId(index);
+                final PointerTracker tracker = getPointerTracker(id, handler);
+                final int x = (int)me.getX(index);
+                final int y = (int)me.getY(index);
+                tracker.onMoveEvent(x, y, eventTime, me);
+            }
+            return;
+        }
+        final int index = me.getActionIndex();
+        final int x = (int)me.getX(index);
+        final int y = (int)me.getY(index);
         switch (action) {
         case MotionEvent.ACTION_DOWN:
         case MotionEvent.ACTION_POINTER_DOWN:
@@ -881,16 +896,13 @@
         case MotionEvent.ACTION_POINTER_UP:
             onUpEvent(x, y, eventTime);
             break;
-        case MotionEvent.ACTION_MOVE:
-            onMoveEvent(x, y, eventTime, null);
-            break;
         case MotionEvent.ACTION_CANCEL:
             onCancelEvent(x, y, eventTime);
             break;
         }
     }
 
-    public void onDownEvent(final int x, final int y, final long eventTime,
+    private void onDownEvent(final int x, final int y, final long eventTime,
             final KeyEventHandler handler) {
         if (DEBUG_EVENT) {
             printTouchEvent("onDownEvent:", x, y, eventTime);
@@ -1005,7 +1017,7 @@
         }
     }
 
-    public void onMoveEvent(final int x, final int y, final long eventTime, final MotionEvent me) {
+    private void onMoveEvent(final int x, final int y, final long eventTime, final MotionEvent me) {
         if (DEBUG_MOVE_EVENT) {
             printTouchEvent("onMoveEvent:", x, y, eventTime);
         }
@@ -1193,7 +1205,7 @@
         }
     }
 
-    public void onUpEvent(final int x, final int y, final long eventTime) {
+    private void onUpEvent(final int x, final int y, final long eventTime) {
         if (DEBUG_EVENT) {
             printTouchEvent("onUpEvent  :", x, y, eventTime);
         }
@@ -1293,7 +1305,7 @@
         sPointerTrackerQueue.remove(this);
     }
 
-    public void onCancelEvent(final int x, final int y, final long eventTime) {
+    private void onCancelEvent(final int x, final int y, final long eventTime) {
         if (DEBUG_EVENT) {
             printTouchEvent("onCancelEvt:", x, y, eventTime);
         }
diff --git a/java/src/com/android/inputmethod/keyboard/internal/GestureTrailsPreview.java b/java/src/com/android/inputmethod/keyboard/internal/GestureTrailsPreview.java
index d4c2594..19e9955 100644
--- a/java/src/com/android/inputmethod/keyboard/internal/GestureTrailsPreview.java
+++ b/java/src/com/android/inputmethod/keyboard/internal/GestureTrailsPreview.java
@@ -110,6 +110,7 @@
 
     private void freeOffscreenBuffer() {
         mOffscreenCanvas.setBitmap(null);
+        mOffscreenCanvas.setMatrix(null);
         if (mOffscreenBuffer != null) {
             mOffscreenBuffer.recycle();
             mOffscreenBuffer = null;
diff --git a/java/src/com/android/inputmethod/keyboard/internal/NonDistinctMultitouchHelper.java b/java/src/com/android/inputmethod/keyboard/internal/NonDistinctMultitouchHelper.java
index 53fff69..a0935b9 100644
--- a/java/src/com/android/inputmethod/keyboard/internal/NonDistinctMultitouchHelper.java
+++ b/java/src/com/android/inputmethod/keyboard/internal/NonDistinctMultitouchHelper.java
@@ -29,56 +29,67 @@
 
     private int mOldPointerCount = 1;
     private Key mOldKey;
+    private int[] mLastCoords = CoordinateUtils.newInstance();
 
     public void processMotionEvent(final MotionEvent me, final KeyEventHandler keyEventHandler) {
         final int pointerCount = me.getPointerCount();
         final int oldPointerCount = mOldPointerCount;
         mOldPointerCount = pointerCount;
-        // Ignore continuous multitouch events because we can't trust the coordinates in mulitouch
-        // events.
+        // Ignore continuous multi-touch events because we can't trust the coordinates
+        // in multi-touch events.
         if (pointerCount > 1 && oldPointerCount > 1) {
             return;
         }
 
+        // Use only main (id=0) pointer tracker.
+        final PointerTracker mainTracker = PointerTracker.getPointerTracker(0, keyEventHandler);
         final int action = me.getActionMasked();
         final int index = me.getActionIndex();
         final long eventTime = me.getEventTime();
-        final int x = (int)me.getX(index);
-        final int y = (int)me.getY(index);
-        // Use only main (id=0) pointer tracker.
-        final PointerTracker mainTracker = PointerTracker.getPointerTracker(0, keyEventHandler);
+        final long downTime = me.getDownTime();
 
-        // In single touch.
+        // In single-touch.
         if (oldPointerCount == 1 && pointerCount == 1) {
-            mainTracker.processMotionEvent(action, x, y, eventTime, keyEventHandler);
+            if (me.getPointerId(index) == mainTracker.mPointerId) {
+                mainTracker.processMotionEvent(me, keyEventHandler);
+                return;
+            }
+            // Inject a copied event.
+            injectMotionEvent(action, me.getX(index), me.getY(index), downTime, eventTime,
+                    mainTracker, keyEventHandler);
             return;
         }
 
         // Single-touch to multi-touch transition.
         if (oldPointerCount == 1 && pointerCount == 2) {
-            // Send an up event for the last pointer, be cause we can't trust the corrdinates of
-            // this multitouch event.
-            final int[] lastCoords = CoordinateUtils.newInstance();
-            mainTracker.getLastCoordinates(lastCoords);
-            mOldKey = mainTracker.getKeyOn(
-                    CoordinateUtils.x(lastCoords), CoordinateUtils.y(lastCoords));
-            // TODO: Stop calling PointerTracker.onUpEvent directly.
-            mainTracker.onUpEvent(
-                    CoordinateUtils.x(lastCoords), CoordinateUtils.y(lastCoords), eventTime);
+            // Send an up event for the last pointer, be cause we can't trust the coordinates of
+            // this multi-touch event.
+            mainTracker.getLastCoordinates(mLastCoords);
+            final int x = CoordinateUtils.x(mLastCoords);
+            final int y = CoordinateUtils.y(mLastCoords);
+            mOldKey = mainTracker.getKeyOn(x, y);
+            // Inject an artifact up event for the old key.
+            injectMotionEvent(MotionEvent.ACTION_UP, x, y, downTime, eventTime,
+                    mainTracker, keyEventHandler);
             return;
         }
 
-        // Multi-touch to single touch transition.
+        // Multi-touch to single-touch transition.
         if (oldPointerCount == 2 && pointerCount == 1) {
-            // Send a down event for the latest pointer if the key is different from the
-            // previous key.
+            // Send a down event for the latest pointer if the key is different from the previous
+            // key.
+            final int x = (int)me.getX(index);
+            final int y = (int)me.getY(index);
             final Key newKey = mainTracker.getKeyOn(x, y);
             if (mOldKey != newKey) {
-                // TODO: Stop calling PointerTracker.onDownEvent directly.
-                mainTracker.onDownEvent(x, y, eventTime, keyEventHandler);
+                // Inject an artifact down event for the new key.
+                // An artifact up event for the new key will usually be injected as a single-touch.
+                injectMotionEvent(MotionEvent.ACTION_DOWN, x, y, downTime, eventTime,
+                        mainTracker, keyEventHandler);
                 if (action == MotionEvent.ACTION_UP) {
-                    // TODO: Stop calling PointerTracker.onUpEvent directly.
-                    mainTracker.onUpEvent(x, y, eventTime);
+                    // Inject an artifact up event for the new key also.
+                    injectMotionEvent(MotionEvent.ACTION_UP, x, y, downTime, eventTime,
+                            mainTracker, keyEventHandler);
                 }
             }
             return;
@@ -87,4 +98,16 @@
         Log.w(TAG, "Unknown touch panel behavior: pointer count is "
                 + pointerCount + " (previously " + oldPointerCount + ")");
     }
+
+    private static void injectMotionEvent(final int action, final float x, final float y,
+            final long downTime, final long eventTime, final PointerTracker tracker,
+            final KeyEventHandler handler) {
+        final MotionEvent me = MotionEvent.obtain(
+                downTime, eventTime, action, x, y, 0 /* metaState */);
+        try {
+            tracker.processMotionEvent(me, handler);
+        } finally {
+            me.recycle();
+        }
+    }
 }
diff --git a/java/src/com/android/inputmethod/keyboard/internal/PreviewPlacerView.java b/java/src/com/android/inputmethod/keyboard/internal/PreviewPlacerView.java
index 3388c57..4c8607d 100644
--- a/java/src/com/android/inputmethod/keyboard/internal/PreviewPlacerView.java
+++ b/java/src/com/android/inputmethod/keyboard/internal/PreviewPlacerView.java
@@ -37,7 +37,10 @@
     public PreviewPlacerView(final Context context, final AttributeSet attrs) {
         super(context, attrs);
         setWillNotDraw(false);
+    }
 
+    public void setHardwareAcceleratedDrawingEnabled(final boolean enabled) {
+        if (!enabled) return;
         final Paint layerPaint = new Paint();
         layerPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_OVER));
         setLayerType(LAYER_TYPE_HARDWARE, layerPaint);
diff --git a/java/src/com/android/inputmethod/latin/settings/Settings.java b/java/src/com/android/inputmethod/latin/settings/Settings.java
index e6a0c07..d432087 100644
--- a/java/src/com/android/inputmethod/latin/settings/Settings.java
+++ b/java/src/com/android/inputmethod/latin/settings/Settings.java
@@ -27,12 +27,14 @@
 import com.android.inputmethod.latin.InputAttributes;
 import com.android.inputmethod.latin.R;
 import com.android.inputmethod.latin.utils.AdditionalSubtypeUtils;
+import com.android.inputmethod.latin.utils.DebugLogUtils;
 import com.android.inputmethod.latin.utils.LocaleUtils;
 import com.android.inputmethod.latin.utils.ResourceUtils;
 import com.android.inputmethod.latin.utils.RunInLocale;
 
 import java.util.HashMap;
 import java.util.Locale;
+import java.util.concurrent.locks.ReentrantLock;
 
 public final class Settings implements SharedPreferences.OnSharedPreferenceChangeListener {
     private static final String TAG = Settings.class.getSimpleName();
@@ -94,6 +96,7 @@
     private Resources mRes;
     private SharedPreferences mPrefs;
     private SettingsValues mSettingsValues;
+    private final ReentrantLock mSettingsValuesLock = new ReentrantLock();
 
     private static final Settings sInstance = new Settings();
 
@@ -121,24 +124,34 @@
 
     @Override
     public void onSharedPreferenceChanged(final SharedPreferences prefs, final String key) {
-        if (mSettingsValues == null) {
-            // TODO: Introduce a static function to register this class and ensure that
-            // loadSettings must be called before "onSharedPreferenceChanged" is called.
-            Log.w(TAG, "onSharedPreferenceChanged called before loadSettings.");
-            return;
+        mSettingsValuesLock.lock();
+        try {
+            if (mSettingsValues == null) {
+                // TODO: Introduce a static function to register this class and ensure that
+                // loadSettings must be called before "onSharedPreferenceChanged" is called.
+                Log.w(TAG, "onSharedPreferenceChanged called before loadSettings.");
+                return;
+            }
+            loadSettings(mSettingsValues.mLocale, mSettingsValues.mInputAttributes);
+        } finally {
+            mSettingsValuesLock.unlock();
         }
-        loadSettings(mSettingsValues.mLocale, mSettingsValues.mInputAttributes);
     }
 
     public void loadSettings(final Locale locale, final InputAttributes inputAttributes) {
-        final SharedPreferences prefs = mPrefs;
-        final RunInLocale<SettingsValues> job = new RunInLocale<SettingsValues>() {
-            @Override
-            protected SettingsValues job(final Resources res) {
-                return new SettingsValues(prefs, locale, res, inputAttributes);
-            }
-        };
-        mSettingsValues = job.runInLocale(mRes, locale);
+        mSettingsValuesLock.lock();
+        try {
+            final SharedPreferences prefs = mPrefs;
+            final RunInLocale<SettingsValues> job = new RunInLocale<SettingsValues>() {
+                @Override
+                protected SettingsValues job(final Resources res) {
+                    return new SettingsValues(prefs, locale, res, inputAttributes);
+                }
+            };
+            mSettingsValues = job.runInLocale(mRes, locale);
+        } finally {
+            mSettingsValuesLock.unlock();
+        }
     }
 
     // TODO: Remove this method and add proxy method to SettingsValues.