Re: customize-face: inverse-video does not work when customizing the menu face

[Richard Stallman]

    effect), but there is one subtle issue that is still unresolved.  If the 
    colors of the toolkit menus are unspecified (i.e. Emacs uses whatever 
    defaults are supplied by the toolkit or the X resources), setting the 
    inverse-video attribute of the `menu' face will still have no effect, 
    since we don't know what the colors are, and hence don't set them.

Emacs could figure out what the resources specify
and put those colors into the `menu' face.
Then it would be able to handle inversion of the `menu' face.