notice that these are NESTED DIV containers.
the (absolute) POSITION and the Z-INDEX of a DIV are relative to it's parent container.

also notice that the event handlers, onmouseover and onmouseout, are applied to the DIV elements themselves!
because they are nested, the mouseout event doesn't happen when you roll over the child element(s).

note: this showing and hiding of children will cause errors in Netscape because I haven't made this cross browser compatible.