Hello everyone I never reported it and I didn't find any information on google or mozilla support about this so here it is : I am on windows 7 and I set up my windows start menu vertically. I also have 2 screens. These both points are important. If I put the start menu horizontally I do not have the issue anymore, and If I turn off one screen to have the display only on one screen, I do not have the issue anymore, which is a rare setup I guess so it could explain why this bug has never been detected. HERE IS THE ISSUE I have display issues on website with a big width, even the default add-ons Manager firefox page doesn't display correctly. Here is a screen shot: http://img15.hostingpics.net/pics/368172bugFirefoxDisplay.png So as you can see the disable and remove button on the right are not displayed, and at the bottom there isn't any scroll bar to scroll ! So I have no way to display the information on the right of the page, and it happens on a lot of other website (gmail, etc) It is not such a big issue because my start menu is on my left screen and I can move firefox on the right screen to have a correct display. I still think this is worth reporting this bug. I hope it is clear, feel free to ask questions if you didn't understand.