Abstract theme: content region width problem

Hi, not sure if you're aware of this problem, so I'll post it here.

The content region appears to take the full width, causing it to drop below the left sidebar.
This is using the default Abstract settings. Screenshots with Firebug attached.

I couldn't figure out where it's getting this width from. Maybe the content-region isn't properly nested or so? The content div itself does not have this excessive width.