Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the add-ons is causing the problem (switch to the DEFAULT theme: Tools > Add-ons > Themes).

• Don't make any changes on the Safe mode start window.

See:

• Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

If it does work in Safe-mode then disable all extensions and then try to find which is causing it by enabling one at a time until the problem reappears.

• Use "Disable all add-ons" on the Safe mode start window to disable all extensions.
• Close and restart Firefox after each change via "File > Exit" (Mac: "Firefox > Quit"; Linux: "File > Quit")

Hi Cor-el, Thank you so much for the reply. I tried disabling all my Add-On then restarted FF but it still did the same thing. My problem is when I roll over the listing it's there but it's white and VERY hard to see. In FF3 I used 'Colorful Tabs' and the letters would change to black and were very visible. I didn't have any luck with the Disabling process do you know of anything else I can do to fix it?

I just noticed that the "Grayed out " , inactive letters stay very visible even when I roll over them???? So my problem is only with the 'Active' lists.