This probably won't help your immediate problem but I would have expected others. Your System Details show seven versions of Shockwave Flash, two versions of Adobe PDF Plug-In and two versions of Adobe Shockwave for Director. Someone more expert will give you the neatest way to tidy this up to just the latest versions.

Is that in the Tab bar?

You can try to open a new window to see if that helps.

See also:

• [/questions/1027393] Active Tab has floating chinese characters as well as the tab name how do I get rid of this?

Can you attach a screenshot?

• http://en.wikipedia.org/wiki/Screenshot
• https://support.mozilla.org/kb/how-do-i-create-screenshot-my-problem

• Use a compressed image type like PNG or JPG to save the screenshot
• Make sure that you do not exceed the maximum size of 1 MB

hello wcabinc, some other affected users tied the issue to the mcafee site advisor extension - please try to disable or remove that in case you have it present.

Disable or remove Add-ons

Immediately solved! Thanks!

Note that your System Details list shown a lot of multiple versions of plugins:

Adobe PDF Plug-In For Firefox and Netscape 11.0.9
Adobe PDF Plug-In For Firefox and Netscape 10.1.12

Shockwave Flash 14.0 r0
Shockwave Flash 13.0 r0
Shockwave Flash 15.0 r0
Shockwave Flash 11.6 r602
Shockwave Flash 11.3 r300
Shockwave Flash 11.9 r900
Shockwave Flash 11.5 r502

Adobe Shockwave for Director Netscape plug-in, version 12.0.7.148
Adobe Shockwave for Director Netscape plug-in, version 12.0.2.122 

You can find the installation path of all plugins on the about:plugins page.

• http://kb.mozillazine.org/Issues_related_to_plugins#Identifying_installed_plugins

See this about uninstalling Flash players:

• http://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html

Note that this will remove all installed Flash players.