website frames?

Not sure if this just my system but I've been finding for a while that the webpage frames seem to reset after doing something like post a message. So the left-hand column with Latest Topics goes further left and I have to use the bottom scrollbar to get the whole site back to normal.
This happens when I am on fullscreen (with the netbook) and custom-adjusted (with larger monitor). Using Firefox. I suspect it doesn't happen on fullscreen with the 22" monitor... (I'd check but that computer is at the shop )
This doesn't happen with other websites?
It's like the whole website wants to "centre" itself after I do those tasks.

It isn't happening on my end. I can see all the latest topics clearly, I am using IE as a system. The only thing that I can pick up is there is maybe 2 matchsticks or a couple of letters distance that I can move the scroll bar slider to the left after posting, is this what is happening Wendy.