Fixed|UI|Client: Mouse cursor should never be hidden in Home

When Home was fullscreen, and one would change focus away and then
back to Doomsday, the mouse cursor would be hidden if the task bar
wasn't open. This should never happen in Home, though, where the mouse
needs to be always available.

doomsday/apps/client/src/ui/clientwindow.cpp

@@ -508,7 +508,7 @@ DENG2_PIMPL(ClientWindow)
 
             canvas.trapMouse(false);
         }
-        else if(self.isFullScreen() && !taskBar->isOpen())
+        else if(self.isFullScreen() && !taskBar->isOpen() && DoomsdayApp::isGameLoaded())
         {
             // Trap the mouse again in fullscreen mode.
             canvas.trapMouse();