Hi lafa, I ran into this problem too just now and found a quick workaround In my case, browser.viewport.desktopWidth in about:config was set to 980 while my actual screen resolution width is 1366, changing it to my actual screen width fixes it for me. The steps I did to change it is the following: # In the [[Awesome Bar - Search your Firefox bookmarks, history and tabs from the address bar|address bar]], type '''about:config''' and press the '''Enter''' key. # Search for '''browser.viewport.desktopWidth''' and change its value to your screen width Hope this helps.