Created attachment 97016 [details]
Test case

before hit F11, type something in the text area, so that the scrollbar appears
then, hit F11 to fullscreen and F11 again to go back

*** Bug 489678 has been marked as a duplicate of this bug. ***

Metacity has a check in it (around constraints.c:415) for pre-EWMH clients
which attempt to sham-fullscreen themselves by making their window as big as
the screen. It intercepts this and fullscreens the window instead. This code is
being triggered. The window is not fullscreened at that point where it is
triggered after unfullscreening, and it is exactly as big as the screen.

I need to investigate some more, and I'm not certain, but I think what's
happening here is:

* The GTK window in question does not have a particular size set;
* Hence, unfullscreening merely clears the fullscreen flag and the window stays
fullsize
* Hence, metacity thinks the window is trying to fullscreen itself and returns
it to fullscreen.

I don't know enough about GTK to know why windows without scrollbars should
return to their old size and windows with should not, but I will attempt to
find out (unless anyone here tells me first). What to do next depends on that,
and after that on what the EWMH says, and after that what other WMs do.

Regression since 2.18.  Interesting...

Running the test case against trunk version as today, it works fine. Can somebody confirm this? Has somebody fixed that? Or was it fixed by itself? :)

Indeed, it was fixed by Peter Bloomfield's additional patch from bug 461927.  Guess it pays to add a few extra checks.  :-)

*** This bug has been marked as a duplicate of 461927 ***