Some IE8 users have reported difficulty managing their sites with "menus and buttons end up stacked on top of each other"
If you are experiencing this, the most likely explanation is that you are using Internet Explorer's IE7 compatibility view. Google does not support IE7 so...
- Go to Tools > Compatibility View Settings and make sure "Display all websites in Compatibility View" is NOT checked
- Go to Tools > Developer Tools and make sure the Browser menu in the upper right of the toolbar says "Internet Explorer 8" for both browser mode and document mode
There are screenshots of both these dialogs here: http://blogs.msdn.com/b/ie/archive/2008/08/27/introducing-compatibility-view.aspx