I have been using firefox for a while and firebird before that. I just reformatted my hard drive so I downloaded the newest firefox. Now my site has a horizontal scrollbar on certain pages. Has anything changed with the latest build that might cause this?
I can't think of anything that would be causing this... The things that spring to mind are the screen resolution of your PC - is it the same as it was before? Also, do you have any side panes open in FireFox?
the skins used can have this affect, they can vary by a few pixels the available width, this can be enough to generate a scroll bar in certain circumstances, but this isn't really a firefox problem, it's more often associated with CSS widths being assumed to add up to 100% when they in fact add up to 100% + something, whether through pixel rounding [up] or whatever.
I've seen this, it took a while to figure out, in my case a designer used floats for layout, and his right column is knocked down to under the content in my firefox, not in his [we used different skins], that's because he had assumed 100% width and not taken into account pixel rounding, or a border, or something. This issue in general can be avoided if there is an overall container with width 100%, and subcontainers with widths set relative to the overall container.