I wanted to simulate a popup window using a Panel as a sort of confirmation message box, but serverside and without javascript.  A Google post here by “crjunk” gave me the idea, and it worked GREAT!

...Oh, darn. Except for this little problem with Select boxes which don't use z-index.  So any panel I might wish to display is going to be eaten up with select boxes, like bricks in a wall.

Isn't that special! 

Here's a superb newsgroup thread on it, and the KB on z-index.

Yet another thing to have to suckup and swallow about web application development.  Oh, I understand why things work this way with select boxes and z-index and all that, I just wasn't prepared for it tonight...