Have you noticed

That you can’t remove a movieclip if it’s at a minus depth? Is this on purpose, or is it a glitch?

It’s mentioned in the Flash Limits thread: http://www.kirupa.com/forum/showthread.php?t=16877

Nice thread, thanks for the link.

I wonder why they made minus depths immune to being removed. It could be useful I guess, if you don’t want something removed, instead of placing it on the stage by hand, just attach it at -1.