What sets the width of forum posts?

[richy96]

Hi

I have a problem with my site - this may be related to other mods I have done.... but anyway

What sets the width of the forum posts in a thread?

I have a lot of threads that display correctly - inspecting the elements show the width of the thread posts themselves are always 605 (pixels?)

Some threads display much too wide and these always seem to be 929 pixels wide - then on the same thread go to page 2 or 3 and that one may display the correct width

I also have some threads which display a bit to wide and these seem to be 657 pixels wide

This is obviously related to the content of the thread as far as I know they all start off the correct width (can't be certain about that but I'm pretty sure it is the case at least for ones I create)

I've tried to pin it down to some factor like someones sig, or the fact the thread contains quotes, or attached images, but I can't seem to find the common factor

So what controls the width of this central table with the forum postbits/ posts and are there common causes that can mess it up?

Additional info
My site uses VBa CMPS so has modules displayed vertically, to both sides of the forum thread, and one module across the top of all threads before the page content. This contains some Quick Link buttons and is the same for every thread (generated from the same template) as are the modules to left and right. I use horizontal postbits if that is relevant

Rich