I've been using Mozilla Firefox 2.0.0.x under Windows XP and I have found a clue to the source of the problem that can be seen when resizing the Firefox browser window horizontally and the [Firefox] vertical scroll scroll bar - at some seemingly arbitrary point - disapears under the right edge of the shrinking window.
I tried to look this problem up using Google, but I didn't find much - just some forum posts on a forum I've already forgotten the name and URI of. However, there was a vital clue in the lengthy thread which didn't apply to my situation directly: the problem is triggered by some characteristic or behavior of the Status Line.
There was also some other mention of the Status bar in the threads I looked at. Someone complained that when they removed the weather.com widget from their status bar the problem cleared...
To make a long story short, I had installed a fairly large number of widgets ("add-ons") that took over various bits and chunks of the status line.
The point at which the vertical scroll bar disappears is the point at which the status bar reaches its minimum possible width based on the combined widths of whatever widgets you have installed on the status bar.
Simple, huh? Well, it took me a minute to work it out, so I thought I would share...
