bug#10873: 24.0.93; `report-emacs-bug' obscures bug-reporting buffer (!)

[martin rudalics <rudalics@gmx.at>]

 >> I consider the window showing *Completions* modal.
 >
 > That's clear.  But what is your reason (evidence) for saying
 > that.

That if you don't consider the window modal you will run into all sorts
of problems like the one that is the subject of this thread.  I'll give
you a more realistic scenario.  Assume that you have a directory ~/foo/
with two files say foo1 and foo2 and a directory ~/bar/ with two files
say bar1 and bar2.  Now do

emacs -Q

M-x customize-option RET abbrev-file-name RET

Put ~/foo/ into the editable field, point at its end and do

M-x widget-complete RET

Now do

C-x 5 2

M-x customize-option RET custom-file RET

Select "File", put ~/bar/ into the editable field, point at its end and
do

M-x widget-complete RET

again.  Note that at this moment you have changed the contents of the
*Completions* windows in _both_ frames.  If you now return to the first
frame and select a completion like bar1, nothing will happen (in the
best case).

This is the same cockpit error as the one from your scenario:
*Completions* windows are modal and should be treated accordingly, that
is, nicely.

 > Ah, so that's what you mean by "modal window".  Not that a user
 > is prevented from doing something else than interact with it,

A user is allowed to do something else as long as she behaves nicely.
That's the price she has to pay for not being "prevented from doing
something else than interact with it".  The user in the scenario above
does not behave nicely and neither do you when you want to report a bug
while the *Completions* windows is shown.  Such users are punished.

 > but that (a) it remains visible until (b) it is no longer needed,
 > when it disappears.
 >
 > That is not the usual meaning of "modal", but OK, good to know.
 >
 > I imagine that (a) is unnecessary, unless you are suggesting
 > that a user cannot remove such a window.  I'm guessing that
 > you perhaps mean, by (a), that no other automatically displayed
 > window takes its place, and that it is not otherwise removed
 > automatically.

All assumptions are off when you violate (a) or (b).

martin