I have also thought how an application launch interface could behave.
To be simple and intuitive I think it should build on the same usage
patterns as other applications. I have come to wonder - why not treat
the application launch interface (be it a start menu or something
fancier) as a started application, rather than as a special button in
the taskbar? Treating it like a regular application window would give
these usability benefits:

o It would be accessible like other started applications. Opening the
ALI with the keyboard would not require any special keybindings, just
regular alt-tab-tab-tab until you focus on it to bring it forward, and
then navigate in it with tab or arrow keys. That is more intuitive
than using something like ALT-F1 to bring it up

o It would simplify the layout of a task bar. As the first started
application, it would naturially reside in the lower left corner and
as further windows are opened they would fill from left to right.

o Regular window operations could work on it, like always in front,
resize, moving around etc.

I think the only special properties it should have is that it should
always be started, and not be easily closed.

Claes