Random scroll bar next to boards/categories.

[Frosty225]

So I was using some of these templates and such and I added the Collapsible Category template and I ended up with a second scroll bar right next to my navigation bar and it bleeds out all the way down my site. How do I fix this?

Edit: I just found out that the scroll bar disappears if the first 4 categories are expanded and shows up if those same first 4 categories are collapsed.  

[La Lune Mauve]

Yeah, I'm getting the same thing on the profile page.

-- though, not because of that code, because I don't have that code
moontest.freemessageboards.com/

I've found this happens only around my border around forum code, which is the CSS code Shrike posted here. Because using the "Ad above Welcometable" code, the border goes under the ad as well, and it makes the Add scroll with the rest of the section. If I use the template mod Shrike posted here, the ad isn't within the border and doesn't scroll either.