What are you using as the homepage?

Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac=Options) key, and then starting Firefox. Is the problem still there?

The problem seems to go away.

The problem does go away in safe mode. Changing homepage did not cure the problem, If I wait a couple of minutes it starts operating normally. Annoying

You can check for problems with current Shockwave Flash plugin versions and hardware acceleration in Firefox and try this:

• make sure you have the latest Flash version:
  http://www.adobe.com/special/products/flashplayer/fp_distribution3.html
• disable hardware acceleration in Firefox
  https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration
• disable protected mode in the Flash plugin (Windows Vista and later)
  https://support.mozilla.org/kb/adobe-flash-protected-mode-firefox
• disable hardware acceleration in the Flash plugin
  https://helpx.adobe.com/flash-player/kb/video-playback-issues.html

See also:

• http://kb.mozillazine.org/Flash#Troubleshooting

I updated Adobe Flash again (updated earlier today) and this seemed to cure the problem. Maybe there was a Flash issue that was corrected?

It seems I was premature in declaring the problem solved. This morning it has returned. Is anyone else having this problem?