Minor When Front-End page have a lot of data, then scrollbars are displayed. When using "Edit" button (to edit cms block content) button on such page, then cms block edit form is opened (it's ok). Problem happens, when you try to maximize this window. Maximized window position and size are calculated based on window size when scrollbars are not present. In this case scrollbar brokes all calculations.
I propose to do following (in thickbox.js in "core/admin_templates/js" folder):
1. Set "overflow: hidden", when first windows is opened.
2. Set it back to original value, when last windows is closed.
This will help to prevent vertical scrollbar when window is maximized (like FCKEditor).