Based on some observations here...

Awerby - try widening the browser pane and see if that helps.

Eddie - what seems to be happening is that there is a problem in how the first and last post shown on a page are adjusted as the browser pane is reduced. I could reproduce AW's issue by narrowing my Firefox browser window. The first and last posts shrink down to only showing one character width far sooner than they should. Posts in-between the first and last on a page seem to resize properly.

EDIT: Actually, you can see the symptom of the issue on any page - the first and posts have far more white space on the right side than the posts in-between.