Try the Firefox SafeMode to see how it works there.
A troubleshooting mode, which disables most Add-ons.
Troubleshoot Firefox issues using Firefox SafeMode

When in Safe Mode...

• The status of plug-ins is not affected.
• Custom preferences are not affected.
• All extensions are disabled.
• The default theme is used, without a persona.
• userChrome.css and userContent.css are ignored.
• The default toolbar layout is used.
• The JIT Javascript compiler is disabled.
• Hardware acceleration is disabled.

• You can open the Firefox 15.0+ SafeMode by holding the Shft key when you use the Firefox desktop or Start menu shortcut.
• Or use the Help menu item, click on Restart with Add-ons Disabled... while Firefox is running.

To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before using the Firefox shortcut (without the Shft key) to open it again.

If it is good in the Firefox SafeMode, your problem is probably caused by an extension, and you need to figure out which one.
http://support.mozilla.com/en-US/kb/troubleshooting+extensions+and+themes

When you figure out what is causing that, please let us know. It might help other user's who have that problem.

Followed the advise on both and the only extension listed was for Java control update (which I get upgraded every day--grr). It was actually disabled although it was installed so I clicked on enable. That seems to have gotten rid of this horrible problem. Thanks so much for your help. No off to solve quirks in Firefox on y android!

Louise

If it happens again the try to close and restart Firefox if you hadn't done this.
That is usually the first to try with such erratic behavior.

Thank you, Iusually do that first thing with any computer problems. Old school computer fix. Hard Boot regardless! lol Thanks again.