Index: /trunk/src/VBox/Frontends/VirtualBox/src/runtime/fullscreen/UIMachineLogicFullscreen.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/runtime/fullscreen/UIMachineLogicFullscreen.cpp	(revision 51246)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/runtime/fullscreen/UIMachineLogicFullscreen.cpp	(revision 51247)
@@ -131,5 +131,6 @@
     QSet<UIMachineWindow*> visibleMachineWindows;
     foreach (UIMachineWindow *pMachineWindow, machineWindows())
-        if (uisession()->isScreenVisible(pMachineWindow->screenId()))
+        if (   uisession()->isScreenVisible(pMachineWindow->screenId())
+            && hasHostScreenForGuestScreen(pMachineWindow->screenId()))
             visibleMachineWindows << pMachineWindow;
     if (   !darwinScreensHaveSeparateSpaces()