If one goes through a series of steps the view in the fixed-size preference pane is laid partially on top of the toolbar.
1. Click "Preferences" button
2. Click "Advanced" tab
3. Click Zoom (green) button
4. Click "General" tab
5. Click Zoom (green) button
6. See the doom of everlasting NSView chaos (also known as the bug)
Link to screen recoding reproducing the above steps: http://cl.ly/FtxX
Link to picture showing aforementioned bug: http://cl.ly/FuZn
Thank you for the problem report! I will investigate into this when I have time.