Re: C-l while in menu?

[Richard Stallman]

    But a useful option might be to make it so that M-f invokes
    forward-word where as <meta> f invokes the file menu.  (With this I
    mean that the user presses and then releases the Meta or Alt key or
    whatever this key to the left of the space bar is labeled.)

That could be weird, but it might be ok.
It is much better than stealing the M-f command.