Tap here to go to the mobile version of the site.
Your Firefox is out of date and may contain a security risk! Upgrade Firefox

Support Forum

FF 19.0 keeps switching to full-screen mode


This is most annoying! I'll be happily working away when suddenly all my toolbars disappear. At first I had no idea what was going on, and would have to close and reopen FF to get them back, then I discovered that the browser was just switching arbitrarily into full screen mode. I've looked to see if maybe there is something in an inconvenient place that I'm accidentally clicking on to cause this, but no. It just happens for no reason. Is there a fix for this?

Additional System Details

Installed Plug-ins

  • Google Update
  • Shockwave Flash 11.5 r502
  • Google Talk Plugin Video Accelerator version:
  • Version
  • VLC media player Web Plugin 2.0.2
  • 4.1.10329.0
  • iTunes Detector Plug-in
  • Adobe Shockwave for Director Netscape plug-in, version
  • DivX Plus Web Player version
  • GEPlugin
  • DivX VOD Helper Plug-in
  • Foxit Reader Plug-In For Firefox and Netscape
  • Motive Plugin for Mozilla Browsers
  • Windows Presentation Foundation (WPF) plug-in for Mozilla browsers
  • PDF-XChange Viewer Netscape Gecko Plugin


  • User Agent: Mozilla/5.0 (Windows NT 6.0; rv:19.0) Gecko/20100101 Firefox/19.0

More Information

  • Top 10 Contributor
  • Moderator
10754 solutions 96791 answers

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

  • Do NOT click the Reset button on the Safe mode start window or otherwise make changes.

Question owner

Sorry, should have said I already did that. Not the problem.

  • Top 10 Contributor
  • Moderator
10754 solutions 96791 answers

You may have a (hardware) problem with the F11 key on your keyboard.

Modified by cor-el

Question owner

For some reason, this has suddenly stopped happening. Browsers are weird sometimes.