diff --git a/services/core/java/com/android/server/wm/DisplayContent.java b/services/core/java/com/android/server/wm/DisplayContent.java
index 30589b1c27a01..c6c26663adcae 100644
--- a/services/core/java/com/android/server/wm/DisplayContent.java
+++ b/services/core/java/com/android/server/wm/DisplayContent.java
@@ -241,6 +241,7 @@ class DisplayContent {
                 mTouchExcludeRegion.op(mTmpRect, Region.Op.DIFFERENCE);
             }
         }
+        mTapDetector.setTouchExcludeRegion(mTouchExcludeRegion);
     }
 
     void switchUserStacks(int newUserId) {
diff --git a/services/core/java/com/android/server/wm/StackTapPointerEventListener.java b/services/core/java/com/android/server/wm/StackTapPointerEventListener.java
index 80eb453cdfeab..1a85993b69af6 100644
--- a/services/core/java/com/android/server/wm/StackTapPointerEventListener.java
+++ b/services/core/java/com/android/server/wm/StackTapPointerEventListener.java
@@ -31,7 +31,7 @@ public class StackTapPointerEventListener implements PointerEventListener {
     private float mDownX;
     private float mDownY;
     private int mPointerId;
-    final private Region mTouchExcludeRegion;
+    final private Region mTouchExcludeRegion = new Region();
     private final WindowManagerService mService;
     private final DisplayContent mDisplayContent;
 
@@ -39,7 +39,6 @@ public class StackTapPointerEventListener implements PointerEventListener {
             DisplayContent displayContent) {
         mService = service;
         mDisplayContent = displayContent;
-        mTouchExcludeRegion = displayContent.mTouchExcludeRegion;
         DisplayInfo info = displayContent.getDisplayInfo();
         mMotionSlop = (int)(info.logicalDensityDpi * TAP_MOTION_SLOP_INCHES);
     }
@@ -72,13 +71,15 @@ public class StackTapPointerEventListener implements PointerEventListener {
                 if (mPointerId == motionEvent.getPointerId(index)) {
                     final int x = (int)motionEvent.getX(index);
                     final int y = (int)motionEvent.getY(index);
-                    if ((motionEvent.getEventTime() - motionEvent.getDownTime())
-                            < TAP_TIMEOUT_MSEC
-                            && Math.abs(x - mDownX) < mMotionSlop
-                            && Math.abs(y - mDownY) < mMotionSlop
-                            && !mTouchExcludeRegion.contains(x, y)) {
-                        mService.mH.obtainMessage(H.TAP_OUTSIDE_STACK, x, y,
-                                mDisplayContent).sendToTarget();
+                    synchronized(this) {
+                        if ((motionEvent.getEventTime() - motionEvent.getDownTime())
+                                < TAP_TIMEOUT_MSEC
+                                && Math.abs(x - mDownX) < mMotionSlop
+                                && Math.abs(y - mDownY) < mMotionSlop
+                                && !mTouchExcludeRegion.contains(x, y)) {
+                            mService.mH.obtainMessage(H.TAP_OUTSIDE_STACK, x, y,
+                                    mDisplayContent).sendToTarget();
+                        }
                     }
                     mPointerId = -1;
                 }
@@ -86,4 +87,10 @@ public class StackTapPointerEventListener implements PointerEventListener {
             }
         }
     }
+
+    void setTouchExcludeRegion(Region newRegion) {
+        synchronized (this) {
+           mTouchExcludeRegion.set(newRegion);
+        }
+    }
 }