diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java
index 2bb3cceb257fe..39fb7936747ed 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java
@@ -22,7 +22,6 @@ import static android.app.WindowConfiguration.WINDOWING_MODE_FULLSCREEN;
 
 import android.app.ActivityManager.RunningTaskInfo;
 import android.content.Context;
-import android.graphics.Rect;
 import android.os.Handler;
 import android.os.IBinder;
 import android.util.SparseArray;
@@ -186,8 +185,9 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel {
                         mSyncQueue);
         mWindowDecorByTaskId.put(taskInfo.taskId, windowDecoration);
 
-        final DragPositioningCallback dragPositioningCallback = createDragPositioningCallback(
-                windowDecoration, taskInfo);
+        final DragPositioningCallback dragPositioningCallback =
+                new FluidResizeTaskPositioner(mTaskOrganizer, windowDecoration, mDisplayController,
+                        null /* disallowedAreaForEndBounds */);
         final CaptionTouchEventListener touchEventListener =
                 new CaptionTouchEventListener(taskInfo, dragPositioningCallback);
         windowDecoration.setCaptionListeners(touchEventListener, touchEventListener);
@@ -198,17 +198,6 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel {
         setupCaptionColor(taskInfo, windowDecoration);
     }
 
-    private FluidResizeTaskPositioner createDragPositioningCallback(
-            CaptionWindowDecoration windowDecoration, RunningTaskInfo taskInfo) {
-        final int screenWidth = mDisplayController.getDisplayLayout(taskInfo.displayId).width();
-        final int statusBarHeight = mDisplayController.getDisplayLayout(taskInfo.displayId)
-                .stableInsets().top;
-        final Rect disallowedAreaForEndBounds = new Rect(0, 0, screenWidth,
-                statusBarHeight);
-        return new FluidResizeTaskPositioner(mTaskOrganizer, windowDecoration,
-                    mDisplayController, disallowedAreaForEndBounds);
-    }
-
     private class CaptionTouchEventListener implements
             View.OnClickListener, View.OnTouchListener, DragDetector.MotionEventHandler {
 
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/FluidResizeTaskPositioner.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/FluidResizeTaskPositioner.java
index 9bcb77f03abdb..9f79d212a7b9d 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/FluidResizeTaskPositioner.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/FluidResizeTaskPositioner.java
@@ -21,6 +21,8 @@ import android.graphics.Rect;
 import android.view.SurfaceControl;
 import android.window.WindowContainerTransaction;
 
+import androidx.annotation.Nullable;
+
 import com.android.wm.shell.ShellTaskOrganizer;
 import com.android.wm.shell.common.DisplayController;
 
@@ -42,24 +44,24 @@ class FluidResizeTaskPositioner implements DragPositioningCallback {
     private final Rect mRepositionTaskBounds = new Rect();
     // If a task move (not resize) finishes in this region, the positioner will not attempt to
     // finalize the bounds there using WCT#setBounds
-    private final Rect mDisallowedAreaForEndBounds = new Rect();
+    private final Rect mDisallowedAreaForEndBounds;
     private boolean mHasDragResized;
     private int mCtrlType;
 
     FluidResizeTaskPositioner(ShellTaskOrganizer taskOrganizer, WindowDecoration windowDecoration,
-            DisplayController displayController, Rect disallowedAreaForEndBounds) {
+            DisplayController displayController, @Nullable Rect disallowedAreaForEndBounds) {
         this(taskOrganizer, windowDecoration, displayController, disallowedAreaForEndBounds,
                 dragStartListener -> {}, SurfaceControl.Transaction::new);
     }
 
     FluidResizeTaskPositioner(ShellTaskOrganizer taskOrganizer, WindowDecoration windowDecoration,
-            DisplayController displayController, Rect disallowedAreaForEndBounds,
+            DisplayController displayController, @Nullable Rect disallowedAreaForEndBounds,
             DragPositioningCallbackUtility.DragStartListener dragStartListener,
             Supplier<SurfaceControl.Transaction> supplier) {
         mTaskOrganizer = taskOrganizer;
         mWindowDecoration = windowDecoration;
         mDisplayController = displayController;
-        mDisallowedAreaForEndBounds.set(disallowedAreaForEndBounds);
+        mDisallowedAreaForEndBounds = new Rect(disallowedAreaForEndBounds);
         mDragStartListener = dragStartListener;
         mTransactionSupplier = supplier;
     }