Re: signal handling bogosities

[Richard Stallman]

    In fact I find it confusing (as a user) that it updates mouse-faces almost
    always, but most things only when it's `ready'.

Emacs won't let you *change* text in the buffer until it is `ready',
and of course they don't update until they change.  By contrast, the
locus of mouse highlighting does change, whenever you move the mouse.