Comment 5 for bug 1017668

To recreate:
Press F for fullscreen and allow the mouse pointer to disappear. The ghost bar remains.

To workaround:
Let the pointer fade away, then move the mouse to bring it back and move the pointer over the ghost bar, then allow the cursor to fade away again. Press F to exit fullscreen. Moving the mouse to double-click will just bring the ghost bar back.

The ghost bar is both unresponsive and does not not update.