ok, so now just make sure controls are not hid behind panel.
Enter full screen in Firefox and back out of full screen. That commonly works , but I would suggest a new theme for firefox, I like the chromifox extreme carbon theme my self.
That theme is supper stable and looks nice.
https://addons.mozilla.org/en-US/firefox/addon/chromifox-extreme-carbon/Might also suggest trying another theme for your Ultimate Edition 2.8 lite.