bug#14326: 24.3; Conflict of w32-send-sys-command and set-default-font

[Drew Adams]

> > Is the intention that one cannot change the size, once a frame has
> > been maximized (without first unmaximizing it)?
> 
> There's no such intention.  What Martin is arguing (I think) was that
> in a maximized frame, set-default-font should alway behave as if its
> 2nd argument were non-nil.

Why should it?

Especially given the statement that there is no intention that one must
unmaximize a frame before changing its size.

If we impose such a behavior for `set-default-font' then it means that in that
case there _is_ such an intention: one would need to unmaximize the frame first,
before using `set-default-font' with nil KEEP-SIZE, to make a nil KEEP-SIZE
value (the default!) be respected.  Why such an exception?

(And I guess we are really talking about `set-frame-font', since
`set-default-font' has been obsolete for a long time now.  Even back in Emacs 20
`set-default-font' was just a vestigial alias for `set-frame-font'.  We can
probably stop talking about `set-default-font' now.)