User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:2.0b4) Gecko/20100818 Firefox/4.0b4 Build Identifier: Mozilla/5.0 (Windows NT 6.1; rv:2.0b4) Gecko/20100818 Firefox/4.0b4 When looking at task bar thumbnails it shows tabs that I used to have, but have been closed out. When they are moused over a blank window with a small black square in the top left corner appears. These bad task bar thumbnails tabs cannot be clicked off by the x on the task bar thumbnail. Reproducible: Sometimes Steps to Reproduce: 1.Have Firefox open a long time with computer. 2.Open lots of tabs. 3.Close some of the tabs. 4.(sometimes) Letting computer go to sleep. Actual Results: When this is done then some of the tabs still show up in the task bar thumbnails. Expected Results: It should have deleted them.

I have a bad feeling that this is a tabcandy regression. I did see this from time to time after it landed but have not in recent builds. Can you confirm this on a more recent build?

This is on Firefox beta 4.o build 4.

Yes, I am suggesting that it may have been fixed in the upcoming beta 5 or one of the nightly builds since the beta 4 build.

I'm having problems reproducing this problem, but I to see other TabCandy and tab preview integration issues I will file.

I still see this occasionally.

I had reported this in another bug report. Same problem

Mozilla/5.0 (Windows NT 6.1; rv:2.0b6) Gecko/20100101 Firefox/4.0b6

I'm seeing this issue as well using Minefield (4.0b8pre). Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:2.0b8pre) Gecko/20101013 Firefox/4.0b8pre

I started having this issue with FF 6 beta 5. Windows 7 x64.

Fixed this issue by disabling task bar thumbnails and re-enabling.

This bug is still an issue. There's no 'fix' other than restarting Firefox each time. Now that Windows 7 has overtaken XP (http://gs.statcounter.com/#os-ww-monthly-200910-201110) and is now the world's most common operating system, it'd be good to have the live previews working properly.