Theme Builder

We're having an issue with our preview area. It doesn't show more than 465px worth of content (height). I've tried everything I can think of to remedy this and nothing has worked. I've done all the edits to the CSS and templates and I don't believe I've added or deleted anything that would keep the content from being able to stretch to as much content is needed.

Can anyone point me in a direction to fix this? We're using Confluence 3.0.0_01 w/ Builder 3.