This is more of an fyi post than anything because I didn't immediately find out about this behavior with a quick google search.
When toggling the display style of the tbody between "none" and "block", the FireFox rendering engine causes the resulting table to be completely misrendered. Multiple columns under tbody will be rendered in the first column of the thead - throwing off thead columns greatly. The toggling only makes subsequent renders worse.
IE will render this display style toggling perfectly fine. I have not tested this on any other browsers.