diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/transition/DefaultTransitionHandler.java b/libs/WindowManager/Shell/src/com/android/wm/shell/transition/DefaultTransitionHandler.java
index 34d98ee87dcc5..5af15300d10bb 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/transition/DefaultTransitionHandler.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/transition/DefaultTransitionHandler.java
@@ -419,8 +419,8 @@ public class DefaultTransitionHandler implements Transitions.TransitionHandler {
                     // hasRoundedCorners is currently only enabled for tasks
                     final Context displayContext =
                             mDisplayController.getDisplayContext(change.getTaskInfo().displayId);
-                    cornerRadius =
-                            ScreenDecorationsUtils.getWindowCornerRadius(displayContext);
+                    cornerRadius = displayContext == null ? 0
+                            : ScreenDecorationsUtils.getWindowCornerRadius(displayContext);
                 } else {
                     cornerRadius = 0;
                 }
diff --git a/services/core/java/com/android/server/wm/DisplayContent.java b/services/core/java/com/android/server/wm/DisplayContent.java
index 2c58d92c6f150..0018a1c41c1a6 100644
--- a/services/core/java/com/android/server/wm/DisplayContent.java
+++ b/services/core/java/com/android/server/wm/DisplayContent.java
@@ -3127,12 +3127,16 @@ class DisplayContent extends RootDisplayArea implements WindowManagerPolicy.Disp
         mDisplayPolicy.switchUser();
     }
 
-    @Override
-    void removeIfPossible() {
-        if (isAnimating(TRANSITION | PARENTS)
+    private boolean shouldDeferRemoval() {
+        return isAnimating(TRANSITION | PARENTS)
                 // isAnimating is a legacy transition query and will be removed, so also add a
                 // check for whether this is in a shell-transition when not using legacy.
-                || mTransitionController.inTransition()) {
+                || mTransitionController.isTransitionOnDisplay(this);
+    }
+
+    @Override
+    void removeIfPossible() {
+        if (shouldDeferRemoval()) {
             mDeferredRemoval = true;
             return;
         }
@@ -3161,6 +3165,8 @@ class DisplayContent extends RootDisplayArea implements WindowManagerPolicy.Disp
             mInputMonitor.onDisplayRemoved();
             mWmService.mDisplayNotificationController.dispatchDisplayRemoved(this);
             mWmService.mAccessibilityController.onDisplayRemoved(mDisplayId);
+            mRootWindowContainer.mTaskSupervisor
+                    .getKeyguardController().onDisplayRemoved(mDisplayId);
         } finally {
             mDisplayReady = false;
         }
@@ -3174,7 +3180,8 @@ class DisplayContent extends RootDisplayArea implements WindowManagerPolicy.Disp
     /** Returns true if a removal action is still being deferred. */
     @Override
     boolean handleCompleteDeferredRemoval() {
-        final boolean stillDeferringRemoval = super.handleCompleteDeferredRemoval();
+        final boolean stillDeferringRemoval =
+                super.handleCompleteDeferredRemoval() || shouldDeferRemoval();
 
         if (!stillDeferringRemoval && mDeferredRemoval) {
             removeImmediately();
@@ -5915,8 +5922,6 @@ class DisplayContent extends RootDisplayArea implements WindowManagerPolicy.Disp
             forAllRootTasks(t -> {t.removeIfPossible("releaseSelfIfNeeded");});
         } else if (getTopRootTask() == null) {
             removeIfPossible();
-            mRootWindowContainer.mTaskSupervisor
-                    .getKeyguardController().onDisplayRemoved(mDisplayId);
         }
     }
 
diff --git a/services/core/java/com/android/server/wm/Transition.java b/services/core/java/com/android/server/wm/Transition.java
index 26871c3dc76aa..ab724a3f141b0 100644
--- a/services/core/java/com/android/server/wm/Transition.java
+++ b/services/core/java/com/android/server/wm/Transition.java
@@ -158,8 +158,8 @@ class Transition extends Binder implements BLASTSyncEngine.TransactionReadyListe
     /** The final animation targets derived from participants after promotion. */
     private ArrayList<WindowContainer> mTargets;
 
-    /** The main display running this transition. */
-    private DisplayContent mTargetDisplay;
+    /** The displays that this transition is running on. */
+    private final ArrayList<DisplayContent> mTargetDisplays = new ArrayList<>();
 
     /**
      * Set of participating windowtokens (activity/wallpaper) which are visible at the end of
@@ -209,6 +209,10 @@ class Transition extends Binder implements BLASTSyncEngine.TransactionReadyListe
         return mTransientLaunches != null && mTransientLaunches.contains(activity);
     }
 
+    boolean isOnDisplay(@NonNull DisplayContent dc) {
+        return mTargetDisplays.contains(dc);
+    }
+
     void setSeamlessRotation(@NonNull WindowContainer wc) {
         final ChangeInfo info = mChanges.get(wc);
         if (info == null) return;
@@ -280,6 +284,9 @@ class Transition extends Binder implements BLASTSyncEngine.TransactionReadyListe
             mChanges.put(wc, info);
         }
         mParticipants.add(wc);
+        if (wc.getDisplayContent() != null && !mTargetDisplays.contains(wc.getDisplayContent())) {
+            mTargetDisplays.add(wc.getDisplayContent());
+        }
         if (info.mShowWallpaper) {
             // Collect the wallpaper token (for isWallpaper(wc)) so it is part of the sync set.
             final WindowState wallpaper =
@@ -516,15 +523,23 @@ class Transition extends Binder implements BLASTSyncEngine.TransactionReadyListe
             dc.getInputMonitor().setActiveRecents(null /* activity */, null /* layer */);
         }
 
-        final AsyncRotationController asyncRotationController =
-                mTargetDisplay.getAsyncRotationController();
-        if (asyncRotationController != null) {
-            asyncRotationController.onTransitionFinished();
-        }
-        // Transient-launch activities cannot be IME target (WindowState#canBeImeTarget),
-        // so re-compute in case the IME target is changed after transition.
-        if (mTransientLaunches != null) {
-            mTargetDisplay.computeImeTarget(true /* updateImeTarget */);
+        for (int i = 0; i < mTargetDisplays.size(); ++i) {
+            final DisplayContent dc = mTargetDisplays.get(i);
+            final AsyncRotationController asyncRotationController = dc.getAsyncRotationController();
+            if (asyncRotationController != null) {
+                asyncRotationController.onTransitionFinished();
+            }
+            if (mTransientLaunches != null) {
+                // Transient-launch activities cannot be IME target (WindowState#canBeImeTarget),
+                // so re-compute in case the IME target is changed after transition.
+                for (int t = 0; t < mTransientLaunches.size(); ++t) {
+                    if (mTransientLaunches.valueAt(t).getDisplayContent() == dc) {
+                        dc.computeImeTarget(true /* updateImeTarget */);
+                        break;
+                    }
+                }
+            }
+            dc.handleCompleteDeferredRemoval();
         }
     }
 
@@ -555,19 +570,13 @@ class Transition extends Binder implements BLASTSyncEngine.TransactionReadyListe
             Slog.e(TAG, "Unexpected Sync ID " + syncId + ". Expected " + mSyncId);
             return;
         }
-        boolean hasWallpaper = false;
-        DisplayContent dc = null;
-        for (int i = mParticipants.size() - 1; i >= 0; --i) {
-            final WindowContainer<?> wc = mParticipants.valueAt(i);
-            if (dc == null && wc.mDisplayContent != null) {
-                dc = wc.mDisplayContent;
-            }
-            if (!hasWallpaper && isWallpaper(wc)) {
-                hasWallpaper = true;
-            }
+        if (mTargetDisplays.isEmpty()) {
+            mTargetDisplays.add(mController.mAtm.mRootWindowContainer.getDefaultDisplay());
         }
-        if (dc == null) dc = mController.mAtm.mRootWindowContainer.getDefaultDisplay();
-        mTargetDisplay = dc;
+        // While there can be multiple DC's involved. For now, we just use the first one as
+        // the "primary" one for most things. Eventually, this will need to change, but, for the
+        // time being, we don't have full cross-display transitions so it isn't a problem.
+        final DisplayContent dc = mTargetDisplays.get(0);
 
         if (mState == STATE_ABORT) {
             mController.abort(this);
@@ -577,8 +586,11 @@ class Transition extends Binder implements BLASTSyncEngine.TransactionReadyListe
             return;
         }
         // Ensure that wallpaper visibility is updated with the latest wallpaper target.
-        if (hasWallpaper) {
-            dc.mWallpaperController.adjustWallpaperWindows();
+        for (int i = mParticipants.size() - 1; i >= 0; --i) {
+            final WindowContainer<?> wc = mParticipants.valueAt(i);
+            if (isWallpaper(wc) && wc.getDisplayContent() != null) {
+                wc.getDisplayContent().mWallpaperController.adjustWallpaperWindows();
+            }
         }
 
         mState = STATE_PLAYING;
diff --git a/services/core/java/com/android/server/wm/TransitionController.java b/services/core/java/com/android/server/wm/TransitionController.java
index 3d9d824fe075c..c267cbacdf245 100644
--- a/services/core/java/com/android/server/wm/TransitionController.java
+++ b/services/core/java/com/android/server/wm/TransitionController.java
@@ -256,6 +256,17 @@ class TransitionController {
         return false;
     }
 
+    /** @return {@code true} if wc is in a participant subtree */
+    boolean isTransitionOnDisplay(@NonNull DisplayContent dc) {
+        if (mCollectingTransition != null && mCollectingTransition.isOnDisplay(dc)) {
+            return true;
+        }
+        for (int i = mPlayingTransitions.size() - 1; i >= 0; --i) {
+            if (mPlayingTransitions.get(i).isOnDisplay(dc)) return true;
+        }
+        return false;
+    }
+
     /**
      * @return {@code true} if {@param ar} is part of a transient-launch activity in an active
      * transition.