In OS X, the submenus are drawn incorrectly.
In Explorer 5.2.3 the submenu is offset 1 pixel to the right and 1 pixel down.
In Safari, the submenu is offset 1 pixel to the right (vertical is okay).
In Netscape 7.1 the submenu positioning is correct. (However, the vertical scrollbar is not removed when moving to another menu item.)
I haven't tested for this change in any Windows browsers yet.
Here's a shot of the offset in Explorer-

The following GIF shows the scrollbar issue in Netscape.
