Question Forum width changing wildly!

I want my forum to be the full width of my site.
When a user first comes to the forum to the (default) category view, it does just that:


However, when I then click into a category the width shrinks somewhat:


Then, when you click into an actual thread the width returns to full:


Any ideas how to make it standard across the whole forum?

Someone surely knows the answer to this.

Are you viewing these pages with Internet Explorer 8 or some other browser. If you're using IE8, have you tried switching to "compatibility view"? I know, this isn't a solution; it may not be a work around. It's just a possibility.

I'm using Firefox 3.0.11 :0(

Its known...but i dont find the post where the solution is written in....

Did you define the forum's width by pixels? Try to do it by percent.
Firebug will help you.

Probably it's #Kunena {}
Try to set there a fixed with. If it does not work, add an !important.