Comment 6 for bug 292283

I'm also quite sure that Gtk allows this.

The important question is, if we want it. Or if people should use <Tab> until they're on the right button and press <space>/<enter> there.
One side: The later stops users from accidentally/quickly changing things.
Other side: Anything can be edited later on anyway and fixed.

Maxime: I've changed the bug to "Incomplete" as it might need some discussion. Change as you see fit.