This is a bug caused by flash. Please make sure you have the latest version of Adobe Flash and that add-ons are also not having an impact on this. Please check if all your plugins are up-to-date. To do this, go to the [http://mozilla.com/plugincheck Mozilla Plugin Check site]. Once you're there, the site will check if all your plugins have the latest versions. If you see plugins in the list that have a yellow ''Update'' button or a red ''Update now'' button, please update these immediately. To do so, please click each red or yellow button. Then you should see a site that allows you to download the latest version. Double-click the downloaded file to start the installation and follow the steps mentioned in the installation procedure. ---- '''Try Firefox Safe Mode''' to see if the problem goes away. Safe Mode is a troubleshooting mode, which disables most add-ons. ''(If you're not using it, switch to the Default theme.)'' * You can open Firefox 4.0+ in Safe Mode by holding the '''Shift''' key when you open the Firefox desktop or Start menu shortcut. * Or open the Help menu and click on the '''Restart with Add-ons Disabled...''' menu item while Firefox is running. ''Once you get the pop-up, just select "'Start in Safe Mode"'' '''''If the issue is not present in Firefox Safe Mode''''', your problem is probably caused by an extension, and you need to figure out which one. Please follow the [[Troubleshooting extensions and themes]] article for that. ''To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.'' ''When you figure out what's causing your issues, please let us know. It might help other users who have the same problem.''