diff --git a/src/servers/app/Desktop.cpp b/src/servers/app/Desktop.cpp
index 593bb52e8d..261dd9b5d2 100644
--- a/src/servers/app/Desktop.cpp
+++ b/src/servers/app/Desktop.cpp
@@ -262,7 +262,7 @@ MouseFilter::Filter(BMessage* message, EventTarget** _target, int32* _viewToken,
 		*_target = NULL;
 	}
 
-	fDesktop->SetLastMouseState(where, buttons);
+	fDesktop->SetLastMouseState(where, buttons, window);
 
 	fDesktop->UnlockAllWindows();
 
@@ -311,6 +311,7 @@ Desktop::Desktop(uid_t userID)
 
 	fMouseEventWindow(NULL),
 	fWindowUnderMouse(NULL),
+	fLockedFocusWindow(NULL),
 	fViewUnderMouse(B_NULL_TOKEN),
 	fLastMousePosition(B_ORIGIN),
 	fLastMouseButtons(0),
@@ -750,10 +751,17 @@ Desktop::Cursor() const
 
 
 void
-Desktop::SetLastMouseState(const BPoint& position, int32 buttons)
+Desktop::SetLastMouseState(const BPoint& position, int32 buttons,
+	Window* windowUnderMouse)
 {
+	// The all-window-lock is write-locked.
 	fLastMousePosition = position;
 	fLastMouseButtons = buttons;
+
+	if (fLastMouseButtons == 0 && fLockedFocusWindow) {
+		fLockedFocusWindow = NULL;
+		SetFocusWindow(windowUnderMouse);
+	}
 }
 
 
@@ -1375,9 +1383,13 @@ Desktop::SetFocusWindow(Window* focus)
 	if (!LockAllWindows())
 		return;
 
-	bool hasModal = _WindowHasModal(focus);
+	// test for B_LOCK_WINDOW_FOCUS
+	if (fLockedFocusWindow && focus != fLockedFocusWindow) {
+		UnlockAllWindows();
+		return;
+	}
 
-	// TODO: test for B_LOCK_WINDOW_FOCUS
+	bool hasModal = _WindowHasModal(focus);
 
 	if (focus == fFocus && focus != NULL && !focus->IsHidden()
 		&& (focus->Flags() & B_AVOID_FOCUS) == 0 && !hasModal) {
@@ -1461,6 +1473,23 @@ Desktop::SetFocusWindow(Window* focus)
 }
 
 
+void
+Desktop::SetFocusLocked(const Window* window)
+{
+	AutoWriteLocker _(fWindowLock);
+
+	if (window != NULL) {
+		// Don't allow this to be set when no mouse buttons
+		// are pressed. (BView::SetMouseEventMask() should only be called
+		// from mouse hooks.)
+		if (fLastMouseButtons == 0)
+			return;
+	}
+
+	fLockedFocusWindow = window;
+}
+	
+
 void
 Desktop::_BringWindowsToFront(WindowList& windows, int32 list,
 	bool wereVisible)
diff --git a/src/servers/app/Desktop.h b/src/servers/app/Desktop.h
index 710bdda189..21f9a550e8 100644
--- a/src/servers/app/Desktop.h
+++ b/src/servers/app/Desktop.h
@@ -82,7 +82,7 @@ class Desktop : public MessageLooper, public ScreenOwner {
 		void					SetCursor(ServerCursor* cursor);
 		ServerCursorReference	Cursor() const;
 		void					SetLastMouseState(const BPoint& position,
-									int32 buttons);
+									int32 buttons, Window* windowUnderMouse);
 									// for use by the mouse filter only
 									// both mouse position calls require
 									// the Desktop object to be locked
@@ -164,6 +164,7 @@ class Desktop : public MessageLooper, public ScreenOwner {
 
 		void					SetFocusWindow(Window* window = NULL);
 		EventTarget*			KeyboardEventTarget();
+		void					SetFocusLocked(const Window* window);
 
 		Window*					FindWindowByClientToken(int32 token,
 									team_id teamID);
@@ -303,6 +304,7 @@ class Desktop : public MessageLooper, public ScreenOwner {
 
 		Window*					fMouseEventWindow;
 		const Window*			fWindowUnderMouse;
+		const Window*			fLockedFocusWindow;
 		int32					fViewUnderMouse;
 		BPoint					fLastMousePosition;
 		int32					fLastMouseButtons;
diff --git a/src/servers/app/ServerWindow.cpp b/src/servers/app/ServerWindow.cpp
index 615247d926..c5f4f192a5 100644
--- a/src/servers/app/ServerWindow.cpp
+++ b/src/servers/app/ServerWindow.cpp
@@ -1343,6 +1343,8 @@ fDesktop->LockSingleWindow();
 fDesktop->UnlockSingleWindow();
 				// TODO: possible deadlock
 				if (eventMask != 0 || options != 0) {
+					if (options & B_LOCK_WINDOW_FOCUS)
+						fDesktop->SetFocusLocked(fWindow);
 					fDesktop->EventDispatcher().AddTemporaryListener(EventTarget(),
 						fCurrentView->Token(), eventMask, options);
 				} else {