Um, if you're talking about your transparent canvas (or your popup menu) being its own separate app, distinct from other apps (or the user's "desktop") that make up the things that are always visible, then you might run into some issues with input focus.

I'm a little rusty on the details for X (and I have only limited knowledge of MS-windows), but as a rule, any user input event (mouse click or keystroke) is normally available to only one app: the one that currently holds input focus, which is typically one whose window is on top. So if your "plate glass" interface is always on top, it might be tough to allow the user to interact directly with anything underneath it. (Or perhaps that is your intention?)

If your "always-visible" background and your "usually invisible" control widgets are all part of the same Tk app, then I believe there is a way to handle the input events such that widgets at lower layers get a chance to see them (but I've never tried that, so I'm not sure).

In reply to Re^3: Perl/Tk and Transparent Canvases by graff
in thread Perl/Tk and Transparent Canvases by Mikster

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