I have multiple screens with task bars above each other. When I open firefox in full sceen ( not f11, just the full screen option that windows provides ) on the bottom screen, there seems to be a piece of firefox's top bar overlapping the task bar on the screen above. How do I fix this? This issue has bothered me for quite a while now. The workaround seems to be to set the windows task bar color to white ( to make it less noticable ), but that doesn't solve the problem, it just makes it less visible. Please see the screenshot. When I unfocus Firefox ( by focussing another piece of software, or none ) the white bar disappears.