Problem with sidebar in Mozilla's browsers

[blastbb]

I have strange problem in Mozilla's browsers with sidebar. With completely same code sometimes it show it correctly but sometimes it move sidebar to bottom. I compared code in both examples and it is identical. Since I can't find error, I am asking here for help from you. Here it is page with complete css and javascript used. If you see layout correctly, try refreshing several times and you'll see a problem.

Thanks in advance

[Snookerman]

I refreshed it about 30 times and nothing happened. Have you tried clearing your cache? What version of Firefox are you using?

[blastbb]

Thanks for your reply. It happens in Firefox 3 and SeaMonkey 1.1. When I now opened this page I first saw correct layou, but with first refreshing got broken, and made screenshot with ScreenGrab, which is here. It's not because of cache, because this happens with clean cache too.