diff --git a/java/src/com/android/inputmethod/accessibility/AccessibleKeyboardViewProxy.java b/java/src/com/android/inputmethod/accessibility/AccessibleKeyboardViewProxy.java
index 77940c0..01220a5 100644
--- a/java/src/com/android/inputmethod/accessibility/AccessibleKeyboardViewProxy.java
+++ b/java/src/com/android/inputmethod/accessibility/AccessibleKeyboardViewProxy.java
@@ -105,15 +105,15 @@
     }
 
     /**
-     * Receives motion events when touch exploration is turned on in SDK
-     * versions ICS and higher.
+     * Intercepts touch events before dispatch when touch exploration is turned
+     * on in ICS and higher.
      *
-     * @param event The motion event.
+     * @param event The motion event being dispatched.
      * @return {@code true} if the event is handled
      */
-    public boolean onTouchEvent(MotionEvent event) {
+    public boolean dispatchTouchEvent(MotionEvent event) {
         // To avoid accidental key presses during touch exploration, always drop
-        // non-hover touch events.
+        // touch events generated by the user.
         return false;
     }
 
diff --git a/java/src/com/android/inputmethod/keyboard/Key.java b/java/src/com/android/inputmethod/keyboard/Key.java
index 03c2164..cb120a3 100644
--- a/java/src/com/android/inputmethod/keyboard/Key.java
+++ b/java/src/com/android/inputmethod/keyboard/Key.java
@@ -52,7 +52,7 @@
 /**
  * Class for describing the position and characteristics of a single key in the keyboard.
  */
-public class Key {
+public class Key implements Comparable<Key> {
     private static final String TAG = Key.class.getSimpleName();
 
     /**
@@ -410,7 +410,7 @@
         });
     }
 
-    private boolean equals(final Key o) {
+    private boolean equalsInternal(final Key o) {
         if (this == o) return true;
         return o.mX == mX
                 && o.mY == mY
@@ -428,13 +428,20 @@
     }
 
     @Override
+    public int compareTo(Key o) {
+        if (equalsInternal(o)) return 0;
+        if (mHashCode > o.mHashCode) return 1;
+        return -1;
+    }
+
+    @Override
     public int hashCode() {
         return mHashCode;
     }
 
     @Override
     public boolean equals(final Object o) {
-        return o instanceof Key && equals((Key)o);
+        return o instanceof Key && equalsInternal((Key)o);
     }
 
     @Override
diff --git a/java/src/com/android/inputmethod/keyboard/KeyboardView.java b/java/src/com/android/inputmethod/keyboard/KeyboardView.java
index db3a7b1..27c3cc3 100644
--- a/java/src/com/android/inputmethod/keyboard/KeyboardView.java
+++ b/java/src/com/android/inputmethod/keyboard/KeyboardView.java
@@ -182,7 +182,7 @@
     private final Region mClipRegion = new Region();
     private Bitmap mOffscreenBuffer;
     /** The canvas for the above mutable keyboard bitmap */
-    private Canvas mOffscreenCanvas;
+    private final Canvas mOffscreenCanvas = new Canvas();
     private final Paint mPaint = new Paint();
     private final Paint.FontMetrics mFontMetrics = new Paint.FontMetrics();
     // This sparse array caches key label text height in pixel indexed by key label text size.
@@ -365,7 +365,8 @@
         if (bufferNeedsUpdates || mOffscreenBuffer == null) {
             if (maybeAllocateOffscreenBuffer()) {
                 mInvalidateAllKeys = true;
-                maybeCreateOffscreenCanvas();
+                // TODO: Stop using the offscreen canvas even when in software rendering
+                mOffscreenCanvas.setBitmap(mOffscreenBuffer);
             }
             onDrawKeyboard(mOffscreenCanvas);
         }
@@ -394,15 +395,6 @@
         }
     }
 
-    private void maybeCreateOffscreenCanvas() {
-        // TODO: Stop using the offscreen canvas even when in software rendering
-        if (mOffscreenCanvas != null) {
-            mOffscreenCanvas.setBitmap(mOffscreenBuffer);
-        } else {
-            mOffscreenCanvas = new Canvas(mOffscreenBuffer);
-        }
-    }
-
     private void onDrawKeyboard(final Canvas canvas) {
         if (mKeyboard == null) return;
 
diff --git a/java/src/com/android/inputmethod/keyboard/MainKeyboardView.java b/java/src/com/android/inputmethod/keyboard/MainKeyboardView.java
index f6b66a7..4ed0f58 100644
--- a/java/src/com/android/inputmethod/keyboard/MainKeyboardView.java
+++ b/java/src/com/android/inputmethod/keyboard/MainKeyboardView.java
@@ -661,13 +661,18 @@
     }
 
     @Override
+    public boolean dispatchTouchEvent(MotionEvent event) {
+        if (AccessibilityUtils.getInstance().isTouchExplorationEnabled()) {
+            return AccessibleKeyboardViewProxy.getInstance().dispatchTouchEvent(event);
+        }
+        return super.dispatchTouchEvent(event);
+    }
+
+    @Override
     public boolean onTouchEvent(final MotionEvent me) {
         if (getKeyboard() == null) {
             return false;
         }
-        if (AccessibilityUtils.getInstance().isTouchExplorationEnabled()) {
-            return AccessibleKeyboardViewProxy.getInstance().onTouchEvent(me);
-        }
         return mTouchScreenRegulator.onTouchEvent(me);
     }
 
diff --git a/java/src/com/android/inputmethod/keyboard/internal/GesturePreviewTrail.java b/java/src/com/android/inputmethod/keyboard/internal/GesturePreviewTrail.java
index 95c9572..4311fa7 100644
--- a/java/src/com/android/inputmethod/keyboard/internal/GesturePreviewTrail.java
+++ b/java/src/com/android/inputmethod/keyboard/internal/GesturePreviewTrail.java
@@ -17,9 +17,7 @@
 import android.content.res.TypedArray;
 import android.graphics.Canvas;
 import android.graphics.Paint;
-import android.graphics.PorterDuff;
-import android.graphics.PorterDuffXfermode;
-import android.graphics.Xfermode;
+import android.graphics.Rect;
 import android.os.SystemClock;
 
 import com.android.inputmethod.latin.Constants;
@@ -118,17 +116,16 @@
                 / params.mTrailLingerDuration, 0.0f);
     }
 
-    private final static Xfermode PORTER_DUFF_MODE_SRC =
-            new PorterDuffXfermode(PorterDuff.Mode.SRC);
-
     /**
      * Draw gesture preview trail
      * @param canvas The canvas to draw the gesture preview trail
      * @param paint The paint object to be used to draw the gesture preview trail
+     * @param outBoundsRect the bounding box of this gesture trail drawing
      * @param params The drawing parameters of gesture preview trail
      * @return true if some gesture preview trails remain to be drawn
      */
-    public boolean drawGestureTrail(final Canvas canvas, final Paint paint, final Params params) {
+    public boolean drawGestureTrail(final Canvas canvas, final Paint paint,
+            final Rect outBoundsRect, final Params params) {
         final int trailSize = mEventTimes.getLength();
         if (trailSize == 0) {
             return false;
@@ -149,12 +146,14 @@
         mTrailStartIndex = startIndex;
 
         if (startIndex < trailSize) {
-            int lastX = getXCoordValue(xCoords[startIndex]);
-            int lastY = yCoords[startIndex];
             paint.setColor(params.mTrailColor);
             paint.setStyle(Paint.Style.STROKE);
             paint.setStrokeCap(Paint.Cap.ROUND);
-            paint.setXfermode(PORTER_DUFF_MODE_SRC);
+            int lastX = getXCoordValue(xCoords[startIndex]);
+            int lastY = yCoords[startIndex];
+            float maxWidth = getWidth(sinceDown - eventTimes[startIndex], params);
+            // Initialize bounds rectangle.
+            outBoundsRect.set(lastX, lastY, lastX, lastY);
             for (int i = startIndex + 1; i < trailSize - 1; i++) {
                 final int x = xCoords[i];
                 final int y = yCoords[i];
@@ -166,10 +165,16 @@
                     final float width = getWidth(elapsedTime, params);
                     paint.setStrokeWidth(width);
                     canvas.drawLine(lastX, lastY, x, y, paint);
+                    // Take union for the bounds.
+                    outBoundsRect.union(x, y);
+                    maxWidth = Math.max(maxWidth, width);
                 }
                 lastX = getXCoordValue(x);
                 lastY = y;
             }
+            // Take care of trail line width.
+            final int inset = -((int)maxWidth + 1);
+            outBoundsRect.inset(inset, inset);
         }
 
         final int newSize = trailSize - startIndex;
diff --git a/java/src/com/android/inputmethod/keyboard/internal/KeyboardParams.java b/java/src/com/android/inputmethod/keyboard/internal/KeyboardParams.java
index ab5d31d..e6fe50e 100644
--- a/java/src/com/android/inputmethod/keyboard/internal/KeyboardParams.java
+++ b/java/src/com/android/inputmethod/keyboard/internal/KeyboardParams.java
@@ -24,7 +24,7 @@
 import com.android.inputmethod.latin.CollectionUtils;
 
 import java.util.ArrayList;
-import java.util.HashSet;
+import java.util.TreeSet;
 
 public class KeyboardParams {
     public KeyboardId mId;
@@ -58,7 +58,7 @@
     public int GRID_WIDTH;
     public int GRID_HEIGHT;
 
-    public final HashSet<Key> mKeys = CollectionUtils.newHashSet();
+    public final TreeSet<Key> mKeys = CollectionUtils.newTreeSet(); // ordered set
     public final ArrayList<Key> mShiftKeys = CollectionUtils.newArrayList();
     public final ArrayList<Key> mAltCodeKeysWhileTyping = CollectionUtils.newArrayList();
     public final KeyboardIconsSet mIconsSet = new KeyboardIconsSet();
diff --git a/java/src/com/android/inputmethod/keyboard/internal/MoreKeySpec.java b/java/src/com/android/inputmethod/keyboard/internal/MoreKeySpec.java
index 5da2654..550391b 100644
--- a/java/src/com/android/inputmethod/keyboard/internal/MoreKeySpec.java
+++ b/java/src/com/android/inputmethod/keyboard/internal/MoreKeySpec.java
@@ -16,12 +16,14 @@
 
 package com.android.inputmethod.keyboard.internal;
 
+import android.text.TextUtils;
+
 import com.android.inputmethod.keyboard.Keyboard;
 import com.android.inputmethod.latin.StringUtils;
 
 import java.util.Locale;
 
-public class MoreKeySpec {
+public final class MoreKeySpec {
     public final int mCode;
     public final String mLabel;
     public final String mOutputText;
@@ -47,6 +49,29 @@
     }
 
     @Override
+    public int hashCode() {
+        int hashCode = 1;
+        hashCode = 31 + mCode;
+        hashCode = hashCode * 31 + mIconId;
+        hashCode = hashCode * 31 + (mLabel == null ? 0 : mLabel.hashCode());
+        hashCode = hashCode * 31 + (mOutputText == null ? 0 : mOutputText.hashCode());
+        return hashCode;
+    }
+
+    @Override
+    public boolean equals(final Object o) {
+        if (this == o) return true;
+        if (o instanceof MoreKeySpec) {
+            final MoreKeySpec other = (MoreKeySpec)o;
+            return mCode == other.mCode
+                    && mIconId == other.mIconId
+                    && TextUtils.equals(mLabel, other.mLabel)
+                    && TextUtils.equals(mOutputText, other.mOutputText);
+        }
+        return false;
+    }
+
+    @Override
     public String toString() {
         final String label = (mIconId == KeyboardIconsSet.ICON_UNDEFINED ? mLabel
                 : KeySpecParser.PREFIX_ICON + KeyboardIconsSet.getIconName(mIconId));
diff --git a/java/src/com/android/inputmethod/keyboard/internal/PreviewPlacerView.java b/java/src/com/android/inputmethod/keyboard/internal/PreviewPlacerView.java
index dbde4ef..7104e3a 100644
--- a/java/src/com/android/inputmethod/keyboard/internal/PreviewPlacerView.java
+++ b/java/src/com/android/inputmethod/keyboard/internal/PreviewPlacerView.java
@@ -18,7 +18,9 @@
 
 import android.content.Context;
 import android.content.res.TypedArray;
+import android.graphics.Bitmap;
 import android.graphics.Canvas;
+import android.graphics.Color;
 import android.graphics.Paint;
 import android.graphics.Paint.Align;
 import android.graphics.PorterDuff;
@@ -54,6 +56,10 @@
     private final Params mGesturePreviewTrailParams;
     private final Paint mGesturePaint;
     private boolean mDrawsGesturePreviewTrail;
+    private Bitmap mOffscreenBuffer;
+    private final Canvas mOffscreenCanvas = new Canvas();
+    private final Rect mOffscreenDirtyRect = new Rect();
+    private final Rect mGesturePreviewTrailBoundsRect = new Rect(); // per trail
 
     private final Paint mTextPaint;
     private String mGestureFloatingPreviewText;
@@ -154,6 +160,7 @@
 
         final Paint gesturePaint = new Paint();
         gesturePaint.setAntiAlias(true);
+        gesturePaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC));
         mGesturePaint = gesturePaint;
 
         final Paint textPaint = new Paint();
@@ -199,10 +206,30 @@
     }
 
     @Override
+    protected void onDetachedFromWindow() {
+        if (mOffscreenBuffer != null) {
+            mOffscreenBuffer.recycle();
+            mOffscreenBuffer = null;
+        }
+    }
+
+    @Override
     public void onDraw(final Canvas canvas) {
         super.onDraw(canvas);
         canvas.translate(mXOrigin, mYOrigin);
         if (mDrawsGesturePreviewTrail) {
+            if (mOffscreenBuffer == null) {
+                mOffscreenBuffer = Bitmap.createBitmap(
+                        getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
+                mOffscreenCanvas.setBitmap(mOffscreenBuffer);
+            }
+            if (!mOffscreenDirtyRect.isEmpty()) {
+                // Clear previous dirty rectangle.
+                mGesturePaint.setColor(Color.TRANSPARENT);
+                mGesturePaint.setStyle(Paint.Style.FILL);
+                mOffscreenCanvas.drawRect(mOffscreenDirtyRect, mGesturePaint);
+                mOffscreenDirtyRect.setEmpty();
+            }
             boolean needsUpdatingGesturePreviewTrail = false;
             synchronized (mGesturePreviewTrails) {
                 // Trails count == fingers count that have ever been active.
@@ -210,10 +237,18 @@
                 for (int index = 0; index < trailsCount; index++) {
                     final GesturePreviewTrail trail = mGesturePreviewTrails.valueAt(index);
                     needsUpdatingGesturePreviewTrail |=
-                            trail.drawGestureTrail(canvas, mGesturePaint,
-                                    mGesturePreviewTrailParams);
+                            trail.drawGestureTrail(mOffscreenCanvas, mGesturePaint,
+                                    mGesturePreviewTrailBoundsRect, mGesturePreviewTrailParams);
+                    // {@link #mGesturePreviewTrailBoundsRect} has bounding box of the trail.
+                    mOffscreenDirtyRect.union(mGesturePreviewTrailBoundsRect);
                 }
             }
+            if (!mOffscreenDirtyRect.isEmpty()) {
+                canvas.drawBitmap(mOffscreenBuffer, mOffscreenDirtyRect, mOffscreenDirtyRect,
+                        mGesturePaint);
+                // Note: Defer clearing the dirty rectangle here because we will get cleared
+                // rectangle on the canvas.
+            }
             if (needsUpdatingGesturePreviewTrail) {
                 mDrawingHandler.postUpdateGestureTrailPreview();
             }
@@ -263,7 +298,6 @@
         final float round = mGestureFloatingPreviewRoundRadius;
         paint.setColor(mGestureFloatingPreviewColor);
         canvas.drawRoundRect(rectangle, round, round, paint);
-
         // Paint the text preview
         paint.setColor(mGestureFloatingPreviewTextColor);
         final float textX = rectX + hPad + textWidth / 2.0f;
diff --git a/java/src/com/android/inputmethod/latin/AutoCorrection.java b/java/src/com/android/inputmethod/latin/AutoCorrection.java
index 01ba300..f425e36 100644
--- a/java/src/com/android/inputmethod/latin/AutoCorrection.java
+++ b/java/src/com/android/inputmethod/latin/AutoCorrection.java
@@ -73,11 +73,11 @@
         return maxFreq;
     }
 
-    // Returns true if this isn't in any dictionary.
-    public static boolean isNotAWord(
+    // Returns true if this is in any of the dictionaries.
+    public static boolean isInTheDictionary(
             final ConcurrentHashMap<String, Dictionary> dictionaries,
             final CharSequence word, final boolean ignoreCase) {
-        return !isValidWord(dictionaries, word, ignoreCase);
+        return isValidWord(dictionaries, word, ignoreCase);
     }
 
     public static boolean suggestionExceedsAutoCorrectionThreshold(SuggestedWordInfo suggestion,
diff --git a/java/src/com/android/inputmethod/latin/LatinIME.java b/java/src/com/android/inputmethod/latin/LatinIME.java
index 96c6d6f..78c65e0 100644
--- a/java/src/com/android/inputmethod/latin/LatinIME.java
+++ b/java/src/com/android/inputmethod/latin/LatinIME.java
@@ -733,6 +733,8 @@
         mainKeyboardView.setGesturePreviewMode(mCurrentSettings.mGesturePreviewTrailEnabled,
                 mCurrentSettings.mGestureFloatingPreviewTextEnabled);
 
+        mConnection.resetCachesUponCursorMove(mLastSelectionStart);
+
         if (TRACE) Debug.startMethodTracing("/data/trace/latinime");
     }
 
@@ -839,7 +841,7 @@
             mSpaceState = SPACE_STATE_NONE;
 
             if ((!mWordComposer.isComposingWord()) || selectionChanged || noComposingSpan) {
-                resetEntireInputState();
+                resetEntireInputState(newSelStart);
             }
 
             mHandler.postUpdateShiftState();
@@ -1043,14 +1045,14 @@
 
     // This will reset the whole input state to the starting state. It will clear
     // the composing word, reset the last composed word, tell the inputconnection about it.
-    private void resetEntireInputState() {
+    private void resetEntireInputState(final int newCursorPosition) {
         resetComposingState(true /* alsoResetLastComposedWord */);
         if (mCurrentSettings.mBigramPredictionEnabled) {
             clearSuggestionStrip();
         } else {
             setSuggestionStrip(mCurrentSettings.mSuggestPuncList, false);
         }
-        mConnection.finishComposingText();
+        mConnection.resetCachesUponCursorMove(newCursorPosition);
     }
 
     private void resetComposingState(final boolean alsoResetLastComposedWord) {
@@ -1220,7 +1222,7 @@
         }
     }
 
-    private void sendUpDownEnterOrBackspace(final int code) {
+    private void sendDownUpKeyEventForBackwardCompatibility(final int code) {
         final long eventTime = SystemClock.uptimeMillis();
         mConnection.sendKeyEvent(new KeyEvent(eventTime, eventTime,
                 KeyEvent.ACTION_DOWN, code, 0, 0, KeyCharacterMap.VIRTUAL_KEYBOARD, 0,
@@ -1234,7 +1236,7 @@
         // TODO: Remove this special handling of digit letters.
         // For backward compatibility. See {@link InputMethodService#sendKeyChar(char)}.
         if (code >= '0' && code <= '9') {
-            super.sendKeyChar((char)code);
+            sendDownUpKeyEventForBackwardCompatibility(code - '0' + KeyEvent.KEYCODE_0);
             if (ProductionFlag.IS_EXPERIMENTAL) {
                 ResearchLogger.latinIME_sendKeyCodePoint(code);
             }
@@ -1249,7 +1251,7 @@
             // a hardware keyboard event on pressing enter or delete. This is bad for many
             // reasons (there are race conditions with commits) but some applications are
             // relying on this behavior so we continue to support it for older apps.
-            sendUpDownEnterOrBackspace(KeyEvent.KEYCODE_ENTER);
+            sendDownUpKeyEventForBackwardCompatibility(KeyEvent.KEYCODE_ENTER);
         } else {
             final String text = new String(new int[] { code }, 0, 1);
             mConnection.commitText(text, text.length());
@@ -1525,7 +1527,7 @@
                     // a hardware keyboard event on pressing enter or delete. This is bad for many
                     // reasons (there are race conditions with commits) but some applications are
                     // relying on this behavior so we continue to support it for older apps.
-                    sendUpDownEnterOrBackspace(KeyEvent.KEYCODE_DEL);
+                    sendDownUpKeyEventForBackwardCompatibility(KeyEvent.KEYCODE_DEL);
                 } else {
                     mConnection.deleteSurroundingText(1, 0);
                 }
@@ -1862,7 +1864,11 @@
                     separatorString);
             if (!typedWord.equals(autoCorrection)) {
                 // This will make the correction flash for a short while as a visual clue
-                // to the user that auto-correction happened.
+                // to the user that auto-correction happened. It has no other effect; in particular
+                // note that this won't affect the text inside the text field AT ALL: it only makes
+                // the segment of text starting at the supplied index and running for the length
+                // of the auto-correction flash. At this moment, the "typedWord" argument is
+                // ignored by TextView.
                 mConnection.commitCorrection(
                         new CorrectionInfo(mLastSelectionEnd - typedWord.length(),
                         typedWord, autoCorrection));
@@ -2229,6 +2235,17 @@
         dialog.show();
     }
 
+    public void debugDumpStateAndCrashWithException(final String context) {
+        final StringBuilder s = new StringBuilder();
+        s.append("Target application : ").append(mTargetApplicationInfo.name)
+                .append("\nPackage : ").append(mTargetApplicationInfo.packageName)
+                .append("\nTarget app sdk version : ")
+                .append(mTargetApplicationInfo.targetSdkVersion)
+                .append("\nAttributes : ").append(mCurrentSettings.getInputAttributesDebugString())
+                .append("\nContext : ").append(context);
+        throw new RuntimeException(s.toString());
+    }
+
     @Override
     protected void dump(FileDescriptor fd, PrintWriter fout, String[] args) {
         super.dump(fd, fout, args);
diff --git a/java/src/com/android/inputmethod/latin/RichInputConnection.java b/java/src/com/android/inputmethod/latin/RichInputConnection.java
index 41e59e9..37e1dbb 100644
--- a/java/src/com/android/inputmethod/latin/RichInputConnection.java
+++ b/java/src/com/android/inputmethod/latin/RichInputConnection.java
@@ -33,16 +33,47 @@
 import java.util.regex.Pattern;
 
 /**
- * Wrapper for InputConnection to simplify interaction
+ * Enrichment class for InputConnection to simplify interaction and add functionality.
+ *
+ * This class serves as a wrapper to be able to simply add hooks to any calls to the underlying
+ * InputConnection. It also keeps track of a number of things to avoid having to call upon IPC
+ * all the time to find out what text is in the buffer, when we need it to determine caps mode
+ * for example.
  */
 public class RichInputConnection {
     private static final String TAG = RichInputConnection.class.getSimpleName();
     private static final boolean DBG = false;
+    private static final boolean DEBUG_PREVIOUS_TEXT = false;
     // Provision for a long word pair and a separator
     private static final int LOOKBACK_CHARACTER_NUM = BinaryDictionary.MAX_WORD_LENGTH * 2 + 1;
     private static final Pattern spaceRegex = Pattern.compile("\\s+");
     private static final int INVALID_CURSOR_POSITION = -1;
 
+    /**
+     * This variable contains the value LatinIME thinks the cursor position should be at now.
+     * This is a few steps in advance of what the TextView thinks it is, because TextView will
+     * only know after the IPC calls gets through.
+     */
+    private int mCurrentCursorPosition = INVALID_CURSOR_POSITION; // in chars, not code points
+    /**
+     * This contains the committed text immediately preceding the cursor and the composing
+     * text if any. It is refreshed when the cursor moves by calling upon the TextView.
+     */
+    private StringBuilder mCommittedTextBeforeComposingText = new StringBuilder();
+    /**
+     * This contains the currently composing text, as LatinIME thinks the TextView is seeing it.
+     */
+    private StringBuilder mComposingText = new StringBuilder();
+    /**
+     * This is a one-character string containing the character after the cursor. Since LatinIME
+     * never touches it directly, it's never modified by any means other than re-reading from the
+     * TextView when the cursor position is changed by the user.
+     */
+    private CharSequence mCharAfterTheCursor = "";
+    // A hint on how many characters to cache from the TextView. A good value of this is given by
+    // how many characters we need to be able to almost always find the caps mode.
+    private static final int DEFAULT_TEXT_CACHE_SIZE = 100;
+
     private final InputMethodService mParent;
     InputConnection mIC;
     int mNestLevel;
@@ -52,6 +83,37 @@
         mNestLevel = 0;
     }
 
+    private void checkConsistencyForDebug() {
+        final ExtractedTextRequest r = new ExtractedTextRequest();
+        r.hintMaxChars = 0;
+        r.hintMaxLines = 0;
+        r.token = 1;
+        r.flags = 0;
+        final ExtractedText et = mIC.getExtractedText(r, 0);
+        final CharSequence beforeCursor = getTextBeforeCursor(DEFAULT_TEXT_CACHE_SIZE, 0);
+        final StringBuilder internal = new StringBuilder().append(mCommittedTextBeforeComposingText)
+                .append(mComposingText);
+        if (null == et || null == beforeCursor) return;
+        final int actualLength = Math.min(beforeCursor.length(), internal.length());
+        if (internal.length() > actualLength) {
+            internal.delete(0, internal.length() - actualLength);
+        }
+        final String reference = (beforeCursor.length() <= actualLength) ? beforeCursor.toString()
+                : beforeCursor.subSequence(beforeCursor.length() - actualLength,
+                        beforeCursor.length()).toString();
+        if (et.selectionStart != mCurrentCursorPosition
+                || !(reference.equals(internal.toString()))) {
+            final String context = "Expected cursor position = " + mCurrentCursorPosition
+                    + "\nActual cursor position = " + et.selectionStart
+                    + "\nExpected text = " + internal.length() + " " + internal
+                    + "\nActual text = " + reference.length() + " " + reference;
+            ((LatinIME)mParent).debugDumpStateAndCrashWithException(context);
+        } else {
+            Log.e(TAG, Utils.getStackTrace(2));
+            Log.e(TAG, "Exp <> Actual : " + mCurrentCursorPosition + " <> " + et.selectionStart);
+        }
+    }
+
     public void beginBatchEdit() {
         if (++mNestLevel == 1) {
             mIC = mParent.getCurrentInputConnection();
@@ -65,12 +127,30 @@
                 Log.e(TAG, "Nest level too deep : " + mNestLevel);
             }
         }
+        checkBatchEdit();
+        if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
     }
+
     public void endBatchEdit() {
         if (mNestLevel <= 0) Log.e(TAG, "Batch edit not in progress!"); // TODO: exception instead
         if (--mNestLevel == 0 && null != mIC) {
             mIC.endBatchEdit();
         }
+        if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
+    }
+
+    public void resetCachesUponCursorMove(final int newCursorPosition) {
+        mCurrentCursorPosition = newCursorPosition;
+        mComposingText.setLength(0);
+        mCommittedTextBeforeComposingText.setLength(0);
+        mCommittedTextBeforeComposingText.append(getTextBeforeCursor(DEFAULT_TEXT_CACHE_SIZE, 0));
+        mCharAfterTheCursor = getTextAfterCursor(1, 0);
+        if (null != mIC) {
+            mIC.finishComposingText();
+            if (ProductionFlag.IS_EXPERIMENTAL) {
+                ResearchLogger.richInputConnection_finishComposingText();
+            }
+        }
     }
 
     private void checkBatchEdit() {
@@ -83,6 +163,10 @@
 
     public void finishComposingText() {
         checkBatchEdit();
+        if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
+        mCommittedTextBeforeComposingText.append(mComposingText);
+        mCurrentCursorPosition += mComposingText.length();
+        mComposingText.setLength(0);
         if (null != mIC) {
             mIC.finishComposingText();
             if (ProductionFlag.IS_EXPERIMENTAL) {
@@ -93,6 +177,10 @@
 
     public void commitText(final CharSequence text, final int i) {
         checkBatchEdit();
+        if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
+        mCommittedTextBeforeComposingText.append(text);
+        mCurrentCursorPosition += text.length() - mComposingText.length();
+        mComposingText.setLength(0);
         if (null != mIC) {
             mIC.commitText(text, i);
             if (ProductionFlag.IS_EXPERIMENTAL) {
@@ -121,12 +209,28 @@
 
     public void deleteSurroundingText(final int i, final int j) {
         checkBatchEdit();
+        final int remainingChars = mComposingText.length() - i;
+        if (remainingChars >= 0) {
+            mComposingText.setLength(remainingChars);
+        } else {
+            mComposingText.setLength(0);
+            // Never cut under 0
+            final int len = Math.max(mCommittedTextBeforeComposingText.length()
+                    + remainingChars, 0);
+            mCommittedTextBeforeComposingText.setLength(len);
+        }
+        if (mCurrentCursorPosition > i) {
+            mCurrentCursorPosition -= i;
+        } else {
+            mCurrentCursorPosition = 0;
+        }
         if (null != mIC) {
             mIC.deleteSurroundingText(i, j);
             if (ProductionFlag.IS_EXPERIMENTAL) {
                 ResearchLogger.richInputConnection_deleteSurroundingText(i, j);
             }
         }
+        if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
     }
 
     public void performEditorAction(final int actionId) {
@@ -141,6 +245,44 @@
 
     public void sendKeyEvent(final KeyEvent keyEvent) {
         checkBatchEdit();
+        if (keyEvent.getAction() == KeyEvent.ACTION_DOWN) {
+            if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
+            // This method is only called for enter or backspace when speaking to old
+            // applications (target SDK <= 15), or for digits.
+            // When talking to new applications we never use this method because it's inherently
+            // racy and has unpredictable results, but for backward compatibility we continue
+            // sending the key events for only Enter and Backspace because some applications
+            // mistakenly catch them to do some stuff.
+            switch (keyEvent.getKeyCode()) {
+                case KeyEvent.KEYCODE_ENTER:
+                    mCommittedTextBeforeComposingText.append("\n");
+                    mCurrentCursorPosition += 1;
+                    break;
+                case KeyEvent.KEYCODE_DEL:
+                    if (0 == mComposingText.length()) {
+                        if (mCommittedTextBeforeComposingText.length() > 0) {
+                            mCommittedTextBeforeComposingText.delete(
+                                    mCommittedTextBeforeComposingText.length() - 1,
+                                    mCommittedTextBeforeComposingText.length());
+                        }
+                    } else {
+                        mComposingText.delete(mComposingText.length() - 1, mComposingText.length());
+                    }
+                    if (mCurrentCursorPosition > 0) mCurrentCursorPosition -= 1;
+                    break;
+                case KeyEvent.KEYCODE_UNKNOWN:
+                    if (null != keyEvent.getCharacters()) {
+                        mCommittedTextBeforeComposingText.append(keyEvent.getCharacters());
+                        mCurrentCursorPosition += keyEvent.getCharacters().length();
+                    }
+                    break;
+                default:
+                    final String text = new String(new int[] { keyEvent.getUnicodeChar() }, 0, 1);
+                    mCommittedTextBeforeComposingText.append(text);
+                    mCurrentCursorPosition += text.length();
+                    break;
+            }
+        }
         if (null != mIC) {
             mIC.sendKeyEvent(keyEvent);
             if (ProductionFlag.IS_EXPERIMENTAL) {
@@ -151,48 +293,83 @@
 
     public void setComposingText(final CharSequence text, final int i) {
         checkBatchEdit();
+        if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
+        mCurrentCursorPosition += text.length() - mComposingText.length();
+        mComposingText.setLength(0);
+        mComposingText.append(text);
+        // TODO: support values of i != 1. At this time, this is never called with i != 1.
         if (null != mIC) {
             mIC.setComposingText(text, i);
             if (ProductionFlag.IS_EXPERIMENTAL) {
                 ResearchLogger.richInputConnection_setComposingText(text, i);
             }
         }
+        if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
     }
 
     public void setSelection(final int from, final int to) {
         checkBatchEdit();
+        if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
         if (null != mIC) {
             mIC.setSelection(from, to);
             if (ProductionFlag.IS_EXPERIMENTAL) {
                 ResearchLogger.richInputConnection_setSelection(from, to);
             }
         }
+        mCurrentCursorPosition = from;
+        mCommittedTextBeforeComposingText.setLength(0);
+        mCommittedTextBeforeComposingText.append(getTextBeforeCursor(DEFAULT_TEXT_CACHE_SIZE, 0));
     }
 
     public void commitCorrection(final CorrectionInfo correctionInfo) {
         checkBatchEdit();
+        if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
+        // This has no effect on the text field and does not change its content. It only makes
+        // TextView flash the text for a second based on indices contained in the argument.
         if (null != mIC) {
             mIC.commitCorrection(correctionInfo);
             if (ProductionFlag.IS_EXPERIMENTAL) {
                 ResearchLogger.richInputConnection_commitCorrection(correctionInfo);
             }
         }
+        if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
     }
 
     public void commitCompletion(final CompletionInfo completionInfo) {
         checkBatchEdit();
+        if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
+        final CharSequence text = completionInfo.getText();
+        mCommittedTextBeforeComposingText.append(text);
+        mCurrentCursorPosition += text.length() - mComposingText.length();
+        mComposingText.setLength(0);
         if (null != mIC) {
             mIC.commitCompletion(completionInfo);
             if (ProductionFlag.IS_EXPERIMENTAL) {
                 ResearchLogger.richInputConnection_commitCompletion(completionInfo);
             }
         }
+        if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
     }
 
     public CharSequence getNthPreviousWord(final String sentenceSeperators, final int n) {
         mIC = mParent.getCurrentInputConnection();
         if (null == mIC) return null;
         final CharSequence prev = mIC.getTextBeforeCursor(LOOKBACK_CHARACTER_NUM, 0);
+        if (DEBUG_PREVIOUS_TEXT && null != prev) {
+            final int checkLength = LOOKBACK_CHARACTER_NUM - 1;
+            final String reference = prev.length() <= checkLength ? prev.toString()
+                    : prev.subSequence(prev.length() - checkLength, prev.length()).toString();
+            final StringBuilder internal = new StringBuilder()
+                    .append(mCommittedTextBeforeComposingText).append(mComposingText);
+            if (internal.length() > checkLength) {
+                internal.delete(0, internal.length() - checkLength);
+                if (!(reference.equals(internal.toString()))) {
+                    final String context =
+                            "Expected text = " + internal + "\nActual text = " + reference;
+                    ((LatinIME)mParent).debugDumpStateAndCrashWithException(context);
+                }
+            }
+        }
         return getNthPreviousWord(prev, sentenceSeperators, n);
     }
 
diff --git a/java/src/com/android/inputmethod/latin/Suggest.java b/java/src/com/android/inputmethod/latin/Suggest.java
index 51ed096..f922bc9 100644
--- a/java/src/com/android/inputmethod/latin/Suggest.java
+++ b/java/src/com/android/inputmethod/latin/Suggest.java
@@ -214,10 +214,12 @@
             whitelistedWord = suggestionsSet.first().mWord;
         }
 
+        // The word can be auto-corrected if it has a whitelist entry that is not itself,
+        // or if it's a 2+ characters non-word (i.e. it's not in the dictionary).
         final boolean allowsToBeAutoCorrected = (null != whitelistedWord
                 && !whitelistedWord.equals(consideredWord))
-                || AutoCorrection.isNotAWord(mDictionaries, consideredWord,
-                        wordComposer.isFirstCharCapitalized());
+                || (consideredWord.length() > 1 && !AutoCorrection.isInTheDictionary(mDictionaries,
+                        consideredWord, wordComposer.isFirstCharCapitalized()));
 
         final boolean hasAutoCorrection;
         // TODO: using isCorrectionEnabled here is not very good. It's probably useless, because
diff --git a/java/src/com/android/inputmethod/latin/UserHistoryDictIOUtils.java b/java/src/com/android/inputmethod/latin/UserHistoryDictIOUtils.java
index d6fa661..1f5f1f7 100644
--- a/java/src/com/android/inputmethod/latin/UserHistoryDictIOUtils.java
+++ b/java/src/com/android/inputmethod/latin/UserHistoryDictIOUtils.java
@@ -91,6 +91,11 @@
         public void position(int position) {
             mPosition = position;
         }
+
+        @Override
+        public void put(final byte b) {
+            mBuffer[mPosition++] = b;
+        }
     }
 
     /**
diff --git a/java/src/com/android/inputmethod/latin/makedict/BinaryDictInputOutput.java b/java/src/com/android/inputmethod/latin/makedict/BinaryDictInputOutput.java
index 6775144..fbcb5ea 100644
--- a/java/src/com/android/inputmethod/latin/makedict/BinaryDictInputOutput.java
+++ b/java/src/com/android/inputmethod/latin/makedict/BinaryDictInputOutput.java
@@ -232,6 +232,7 @@
         public int readInt();
         public int position();
         public void position(int newPosition);
+        public void put(final byte b);
     }
 
     public static final class ByteBufferWrapper implements FusionDictionaryBufferInterface {
@@ -271,6 +272,11 @@
         public void position(int newPos) {
             mBuffer.position(newPos);
         }
+
+        @Override
+        public void put(final byte b) {
+            mBuffer.put(b);
+        }
     }
 
     /**
diff --git a/native/jni/src/debug.h b/native/jni/src/debug.h
deleted file mode 100644
index 8f6b69d..0000000
--- a/native/jni/src/debug.h
+++ /dev/null
@@ -1,71 +0,0 @@
-/*
- * Copyright (C) 2011, The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef LATINIME_DEBUG_H
-#define LATINIME_DEBUG_H
-
-#include "defines.h"
-
-static inline unsigned char *convertToUnibyteString(unsigned short *input, unsigned char *output,
-        const unsigned int length) {
-    unsigned int i = 0;
-    for (; i < length && input[i] != 0; ++i)
-        output[i] = input[i] & 0xFF;
-    output[i] = 0;
-    return output;
-}
-
-static inline unsigned char *convertToUnibyteStringAndReplaceLastChar(unsigned short *input,
-        unsigned char *output, const unsigned int length, unsigned char c) {
-    unsigned int i = 0;
-    for (; i < length && input[i] != 0; ++i)
-        output[i] = input[i] & 0xFF;
-    if (i > 0) output[i-1] = c;
-    output[i] = 0;
-    return output;
-}
-
-static inline void LOGI_S16(unsigned short *string, const unsigned int length) {
-    unsigned char tmp_buffer[length];
-    convertToUnibyteString(string, tmp_buffer, length);
-    AKLOGI(">> %s", tmp_buffer);
-    // The log facility is throwing out log that comes too fast. The following
-    // is a dirty way of slowing down processing so that we can see all log.
-    // TODO : refactor this in a blocking log or something.
-    // usleep(10);
-}
-
-static inline void LOGI_S16_PLUS(unsigned short *string, const unsigned int length,
-        unsigned char c) {
-    unsigned char tmp_buffer[length+1];
-    convertToUnibyteStringAndReplaceLastChar(string, tmp_buffer, length, c);
-    AKLOGI(">> %s", tmp_buffer);
-    // Likewise
-    // usleep(10);
-}
-
-static inline void printDebug(const char *tag, int *codes, int codesSize, int MAX_PROXIMITY_CHARS) {
-    unsigned char *buf = static_cast<unsigned char *>(malloc((1 + codesSize) * sizeof(*buf)));
-
-    buf[codesSize] = 0;
-    while (--codesSize >= 0) {
-        buf[codesSize] = static_cast<unsigned char>(codes[codesSize * MAX_PROXIMITY_CHARS]);
-    }
-    AKLOGI("%s, WORD = %s", tag, buf);
-
-    free(buf);
-}
-#endif // LATINIME_DEBUG_H
diff --git a/native/jni/src/defines.h b/native/jni/src/defines.h
index 95a9027..ad526fb 100644
--- a/native/jni/src/defines.h
+++ b/native/jni/src/defines.h
@@ -220,7 +220,11 @@
 #define DEBUG_CORRECTION_FREQ false
 #define DEBUG_WORDS_PRIORITY_QUEUE false
 
+#ifdef FLAG_FULL_DBG
+#define DEBUG_GEO_FULL true
+#else
 #define DEBUG_GEO_FULL false
+#endif
 
 #else // FLAG_DBG
 
diff --git a/native/jni/src/proximity_info_state.cpp b/native/jni/src/proximity_info_state.cpp
index a4eb7e3..208b693 100644
--- a/native/jni/src/proximity_info_state.cpp
+++ b/native/jni/src/proximity_info_state.cpp
@@ -98,6 +98,10 @@
         mDistanceCache.clear();
         mNearKeysVector.clear();
     }
+    if (DEBUG_GEO_FULL) {
+        AKLOGI("Init ProximityInfoState: reused points =  %d, last input size = %d",
+                pushTouchPointStartIndex, lastSavedInputSize);
+    }
     mInputSize = 0;
 
     if (xCoordinates && yCoordinates) {
@@ -109,6 +113,9 @@
                 lastInputIndex = i;
             }
         }
+        if (DEBUG_GEO_FULL) {
+            AKLOGI("Init ProximityInfoState: last input index = %d", lastInputIndex);
+        }
         // Working space to save near keys distances for current, prev and prevprev input point.
         NearKeysDistanceMap nearKeysDistances[3];
         // These pointers are swapped for each inputs points.
@@ -119,13 +126,16 @@
         for (int i = pushTouchPointStartIndex; i <= lastInputIndex; ++i) {
             // Assuming pointerId == 0 if pointerIds is null.
             const int pid = pointerIds ? pointerIds[i] : 0;
+            if (DEBUG_GEO_FULL) {
+                AKLOGI("Init ProximityInfoState: (%d)PID = %d", i, pid);
+            }
             if (pointerId == pid) {
                 const int c = isGeometric ? NOT_A_COORDINATE : getPrimaryCharAt(i);
                 const int x = proximityOnly ? NOT_A_COORDINATE : xCoordinates[i];
                 const int y = proximityOnly ? NOT_A_COORDINATE : yCoordinates[i];
                 const int time = times ? times[i] : -1;
-                if (pushTouchPoint(i, c, x, y, time, isGeometric, i == lastInputIndex,
-                        currentNearKeysDistances, prevNearKeysDistances,
+                if (pushTouchPoint(i, c, x, y, time, isGeometric /* do sampling */,
+                        i == lastInputIndex, currentNearKeysDistances, prevNearKeysDistances,
                         prevPrevNearKeysDistances)) {
                     // Previous point information was popped.
                     NearKeysDistanceMap *tmp = prevNearKeysDistances;
@@ -218,6 +228,10 @@
             }
         }
     }
+
+    if (DEBUG_GEO_FULL) {
+        AKLOGI("ProximityState init finished: %d points out of %d", mInputSize, inputSize);
+    }
 }
 
 bool ProximityInfoState::checkAndReturnIsContinuationPossible(const int inputSize,
@@ -363,6 +377,13 @@
         if (isLastPoint) {
             if (size > 0 && getDistanceFloat(x, y, mInputXs.back(), mInputYs.back())
                     < mProximityInfo->getMostCommonKeyWidth() * LAST_POINT_SKIP_DISTANCE_SCALE) {
+                if (DEBUG_GEO_FULL) {
+                    AKLOGI("p0: size = %zd, x = %d, y = %d, lx = %d, ly = %d, dist = %f, "
+                           "width = %f", size, x, y, mInputXs.back(), mInputYs.back(),
+                           getDistanceFloat(x, y, mInputXs.back(), mInputYs.back()),
+                           mProximityInfo->getMostCommonKeyWidth()
+                                   * LAST_POINT_SKIP_DISTANCE_SCALE);
+                }
                 return popped;
             } else if (size > 1) {
                 int minChar = 0;
@@ -376,6 +397,10 @@
                 }
                 NearKeysDistanceMap::const_iterator itPP =
                         prevNearKeysDistances->find(minChar);
+                if (DEBUG_GEO_FULL) {
+                    AKLOGI("p1: char = %c, minDist = %f, prevNear key minDist = %f",
+                            minChar, itPP->second, minDist);
+                }
                 if (itPP != prevNearKeysDistances->end() && minDist > itPP->second) {
                     return popped;
                 }
@@ -402,6 +427,10 @@
     mInputYs.push_back(y);
     mTimes.push_back(time);
     mInputIndice.push_back(inputIndex);
+    if (DEBUG_GEO_FULL) {
+        AKLOGI("pushTouchPoint: x = %03d, y = %03d, time = %d, index = %d, popped ? %01d",
+                x, y, time, inputIndex, popped);
+    }
     return popped;
 }