Windows 7: Firefox 4 doesn't function properly in the taskbar

This is quite a weird problem and it started when I replaced Firefox 3.6 with Firefox 4 (as in uninstall Firefox and install Firefox 4).
Everytime I am browing now Firefox 4 doesn't function properly in the taskbar. I made a screenshot of it which shows the problem much better.
As you can see Chrome and Foobar2000 are function properly and the way I want it, but Firefox 4 doesn't. It show the open browser and the icon to start another Firefox window and that's not how I want it.
Could anyone help me with this small problem?

I'm not having any problems with FF. I'm using RC1 version... Click on that icon and remove it from taskbar. After that click with right click on firefox icon(that you browse) and select Pin to Taskbar.

1. Click on Help, then "Restart with Add-ons Disabled"; if Firefox is okay then, restart normally. Assuming that you have extensions installed, disabled one-half of them, restart, test, repeat until you find the culprit.

2. If (1.) supra does not avail, then use the link infra to create and test a new Firefox profile:

Profile Manager - MozillaZine Knowledge Base

Such a simple solution, it worked like a charm!
Thanks so much

Repped you.

Thanks for all the help guys

You're welcome ! Glad to help you. Also thanks for the rep!