As far as I know this is not possible. The reason why I think this is because Tk is a layer on top of a windowmanager, which does the kind of control you describe. The way to do it would be to write something at the level of the windowmanager (you could look into the WM:: hierarchy though), which is the level the windows operating system operates at.

Perhaps a better solution for you (if you want to use the Win32 platform) is to use one of the Win32:: modules that are available, like the Win32::GUI ones, but I have no experience with them.

Jouke Visser, Perl 'Adept'