Firefox 5 on Windows XP: Each time a "new" application or any "new" program window launches and I change the focus to Firefox window back again, the Firefox window becomes smaller. E.g. if I start the Windows calculator, change focus to Firefox, Firefox window becomes smaller. If I change the focus to calculator again and then back to Firefox again, this does not happen anymore. But if I start a second calculator instance and then change focus back to Firefox, it happens again. This seems to work with every new launched program and happens (almost) only once the new program instance is launched. It happens on some other occurences with focus change too, but I can not make out the error description for the other occurences exactly. When I minimize Firefox window to task bar and maximize it again, the size is normal full-screen maximized. And then it starts to shrink on and on while I change focus again. Pretty annoying... I also use Windows Blinds for some "better" Windows look, that´s the only addition running on the PC concerning windows "style". But I didn´t have such problems with Firefox 4, so it seems to be a Firefox bug to me.