diff --git a/services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java b/services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java
index 7580b69..49f15e4 100644
--- a/services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java
+++ b/services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java
@@ -3653,6 +3653,12 @@
             return;
         }
 
+        // Magnification connection should not be requested for visible background users.
+        // (b/332222893)
+        if (mUmi.isVisibleBackgroundFullUser(userState.mUserId)) {
+            return;
+        }
+
         final boolean shortcutEnabled = (userState.isShortcutMagnificationEnabledLocked()
                 || userState.isMagnificationSingleFingerTripleTapEnabledLocked()
                 || (Flags.enableMagnificationMultipleFingerMultipleTapGesture()
diff --git a/services/accessibility/java/com/android/server/accessibility/magnification/MagnificationConnectionManager.java b/services/accessibility/java/com/android/server/accessibility/magnification/MagnificationConnectionManager.java
index 19e3e69..fe06406 100644
--- a/services/accessibility/java/com/android/server/accessibility/magnification/MagnificationConnectionManager.java
+++ b/services/accessibility/java/com/android/server/accessibility/magnification/MagnificationConnectionManager.java
@@ -19,6 +19,7 @@
 import static android.accessibilityservice.AccessibilityTrace.FLAGS_MAGNIFICATION_CONNECTION;
 import static android.accessibilityservice.AccessibilityTrace.FLAGS_MAGNIFICATION_CONNECTION_CALLBACK;
 import static android.os.Build.HW_TIMEOUT_MULTIPLIER;
+import static android.os.UserHandle.getCallingUserId;
 import static android.view.accessibility.MagnificationAnimationCallback.STUB_ANIMATION_CALLBACK;
 
 import static com.android.server.accessibility.AccessibilityManagerService.INVALID_SERVICE_ID;
@@ -54,6 +55,7 @@
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.server.LocalServices;
 import com.android.server.accessibility.AccessibilityTraceManager;
+import com.android.server.pm.UserManagerInternal;
 import com.android.server.statusbar.StatusBarManagerInternal;
 import com.android.server.wm.WindowManagerInternal;
 
@@ -209,6 +211,7 @@
     private final Callback mCallback;
     private final AccessibilityTraceManager mTrace;
     private final MagnificationScaleProvider mScaleProvider;
+    private final UserManagerInternal mUserManagerInternal;
 
     public MagnificationConnectionManager(Context context, Object lock, @NonNull Callback callback,
             AccessibilityTraceManager trace, MagnificationScaleProvider scaleProvider) {
@@ -217,6 +220,7 @@
         mCallback = callback;
         mTrace = trace;
         mScaleProvider = scaleProvider;
+        mUserManagerInternal = LocalServices.getService(UserManagerInternal.class);
     }
 
     /**
@@ -280,12 +284,18 @@
      * Requests {@link IMagnificationConnection} through
      * {@link StatusBarManagerInternal#requestMagnificationConnection(boolean)} and
      * destroys all window magnifications if necessary.
+     * NOTE: Currently, this is not allowed to call from visible background users.(b/332222893)
      *
      * @param connect {@code true} if needs connection, otherwise set the connection to null and
      *                destroy all window magnifications.
      * @return {@code true} if {@link IMagnificationConnection} state is going to change.
      */
     public boolean requestConnection(boolean connect) {
+        final int callingUserId = getCallingUserId();
+        if (mUserManagerInternal.isVisibleBackgroundFullUser(callingUserId)) {
+            throw new SecurityException("Visible background user(u" + callingUserId
+                    + " is not permitted to request magnification connection.");
+        }
         if (DBG) {
             Slog.d(TAG, "requestConnection :" + connect);
         }
diff --git a/services/core/java/com/android/server/policy/PhoneWindowManager.java b/services/core/java/com/android/server/policy/PhoneWindowManager.java
index ca60518..e0c4ebe 100644
--- a/services/core/java/com/android/server/policy/PhoneWindowManager.java
+++ b/services/core/java/com/android/server/policy/PhoneWindowManager.java
@@ -734,7 +734,10 @@
                     KeyEvent.KEYCODE_ASSIST,
                     KeyEvent.KEYCODE_VOICE_ASSIST,
                     KeyEvent.KEYCODE_MUTE,
-                    KeyEvent.KEYCODE_VOLUME_MUTE
+                    KeyEvent.KEYCODE_VOLUME_MUTE,
+                    KeyEvent.KEYCODE_RECENT_APPS,
+                    KeyEvent.KEYCODE_APP_SWITCH,
+                    KeyEvent.KEYCODE_NOTIFICATION
             ));
 
     private static final int MSG_DISPATCH_MEDIA_KEY_WITH_WAKE_LOCK = 3;
@@ -2077,12 +2080,21 @@
             }
             switch (mDoubleTapOnHomeBehavior) {
                 case DOUBLE_TAP_HOME_RECENT_SYSTEM_UI:
+                    if (!isKeyEventForCurrentUser(
+                            event.getDisplayId(), event.getKeyCode(), "toggleRecentApps")) {
+                        break;
+                    }
                     notifyKeyGestureCompleted(event,
                             KeyGestureEvent.KEY_GESTURE_TYPE_APP_SWITCH);
                     mHomeConsumed = true;
                     toggleRecentApps();
                     break;
                 case DOUBLE_TAP_HOME_PIP_MENU:
+                    if (!isKeyEventForCurrentUser(
+                            event.getDisplayId(), event.getKeyCode(),
+                            "showPictureInPictureMenu")) {
+                        break;
+                    }
                     mHomeConsumed = true;
                     showPictureInPictureMenuInternal();
                     break;
@@ -2111,12 +2123,20 @@
                     }
                     break;
                 case LONG_PRESS_HOME_ASSIST:
+                    if (!isKeyEventForCurrentUser(
+                            event.getDisplayId(), event.getKeyCode(), "launchAssistAction")) {
+                        break;
+                    }
                     notifyKeyGestureCompleted(event,
                             KeyGestureEvent.KEY_GESTURE_TYPE_LAUNCH_ASSISTANT);
                     launchAssistAction(null, event.getDeviceId(), event.getEventTime(),
                             AssistUtils.INVOCATION_TYPE_HOME_BUTTON_LONG_PRESS);
                     break;
                 case LONG_PRESS_HOME_NOTIFICATION_PANEL:
+                    if (!isKeyEventForCurrentUser(
+                            event.getDisplayId(), event.getKeyCode(), "toggleNotificationPanel")) {
+                        break;
+                    }
                     notifyKeyGestureCompleted(event,
                             KeyGestureEvent.KEY_GESTURE_TYPE_TOGGLE_NOTIFICATION_PANEL);
                     toggleNotificationPanel();
@@ -3477,7 +3497,11 @@
 
         if (isUserSetupComplete() && !keyguardOn) {
             if (mModifierShortcutManager.interceptKey(event)) {
-                dismissKeyboardShortcutsMenu();
+                if (isKeyEventForCurrentUser(
+                        event.getDisplayId(), event.getKeyCode(),
+                        "dismissKeyboardShortcutsMenu")) {
+                    dismissKeyboardShortcutsMenu();
+                }
                 mPendingMetaAction = false;
                 mPendingCapsLockToggle = false;
                 return true;
@@ -4733,7 +4757,10 @@
         }
 
         // no keyguard stuff to worry about, just launch home!
-        if (mRecentsVisible) {
+        // If Recents is visible and the action is not from visible background users,
+        // hide Recents and notify it to launch Home.
+        if (mRecentsVisible
+                && (!mVisibleBackgroundUsersEnabled || displayId == DEFAULT_DISPLAY)) {
             try {
                 ActivityManager.getService().stopAppSwitches();
             } catch (RemoteException e) {}
@@ -5477,6 +5504,9 @@
      * Notify the StatusBar that a system key was pressed.
      */
     private void sendSystemKeyToStatusBar(KeyEvent key) {
+        if (!isKeyEventForCurrentUser(key.getDisplayId(), key.getKeyCode(), "handleSystemKey")) {
+            return;
+        }
         IStatusBarService statusBar = getStatusBarService();
         if (statusBar != null) {
             try {
diff --git a/services/core/java/com/android/server/search/SearchManagerService.java b/services/core/java/com/android/server/search/SearchManagerService.java
index 9b39fa1..a49a9fd 100644
--- a/services/core/java/com/android/server/search/SearchManagerService.java
+++ b/services/core/java/com/android/server/search/SearchManagerService.java
@@ -46,6 +46,7 @@
 import com.android.server.LocalServices;
 import com.android.server.SystemService;
 import com.android.server.SystemService.TargetUser;
+import com.android.server.pm.UserManagerInternal;
 import com.android.server.statusbar.StatusBarManagerInternal;
 
 import java.io.FileDescriptor;
@@ -89,6 +90,8 @@
     @GuardedBy("mSearchables")
     private final SparseArray<Searchables> mSearchables = new SparseArray<>();
 
+    private final UserManagerInternal mUserManagerInternal;
+
     /**
      * Initializes the Search Manager service in the provided system context.
      * Only one instance of this object should be created!
@@ -101,6 +104,7 @@
         mMyPackageMonitor.register(context, null, UserHandle.ALL, true);
         new GlobalSearchProviderObserver(context.getContentResolver());
         mHandler = BackgroundThread.getHandler();
+        mUserManagerInternal = LocalServices.getService(UserManagerInternal.class);
     }
 
     private Searchables getSearchables(int userId) {
@@ -336,6 +340,14 @@
 
     @Override
     public void launchAssist(int userHandle, Bundle args) {
+        // Currently, visible background users are not allowed to launch assist.(b/332222893)
+        // TODO(b/368715893): Consider indirect calls from system service when checking the
+        // calling user.
+        final int callingUserId = UserHandle.getCallingUserId();
+        if (mUserManagerInternal.isVisibleBackgroundFullUser(callingUserId)) {
+            throw new SecurityException("Visible background user(u" + callingUserId
+                    + ") is not permitted to launch assist.");
+        }
         StatusBarManagerInternal statusBarManager =
                 LocalServices.getService(StatusBarManagerInternal.class);
         if (statusBarManager != null) {
diff --git a/services/tests/servicestests/src/com/android/server/accessibility/magnification/MagnificationConnectionManagerTest.java b/services/tests/servicestests/src/com/android/server/accessibility/magnification/MagnificationConnectionManagerTest.java
index 87fe6cf..6d27ddd 100644
--- a/services/tests/servicestests/src/com/android/server/accessibility/magnification/MagnificationConnectionManagerTest.java
+++ b/services/tests/servicestests/src/com/android/server/accessibility/magnification/MagnificationConnectionManagerTest.java
@@ -62,6 +62,7 @@
 import com.android.internal.util.test.FakeSettingsProvider;
 import com.android.server.LocalServices;
 import com.android.server.accessibility.AccessibilityTraceManager;
+import com.android.server.pm.UserManagerInternal;
 import com.android.server.statusbar.StatusBarManagerInternal;
 
 import org.junit.Before;
@@ -92,12 +93,16 @@
     private MagnificationConnectionManager.Callback mMockCallback;
     private MockContentResolver mResolver;
     private MagnificationConnectionManager mMagnificationConnectionManager;
+    @Mock
+    private UserManagerInternal mMockUserManagerInternal;
 
     @Before
     public void setUp() throws RemoteException {
         MockitoAnnotations.initMocks(this);
         LocalServices.removeServiceForTest(StatusBarManagerInternal.class);
+        LocalServices.removeServiceForTest(UserManagerInternal.class);
         LocalServices.addService(StatusBarManagerInternal.class, mMockStatusBarManagerInternal);
+        LocalServices.addService(UserManagerInternal.class, mMockUserManagerInternal);
         mResolver = new MockContentResolver();
         mMockConnection = new MockMagnificationConnection();
         mMagnificationConnectionManager = new MagnificationConnectionManager(mContext, new Object(),
@@ -110,6 +115,8 @@
         Settings.Secure.putFloatForUser(mResolver,
                 Settings.Secure.ACCESSIBILITY_DISPLAY_MAGNIFICATION_SCALE, 2.5f,
                 CURRENT_USER_ID);
+
+        when(mMockUserManagerInternal.isVisibleBackgroundFullUser(anyInt())).thenReturn(false);
     }
 
     private void stubSetConnection(boolean needDelay) {