GTK+, WM, desktops and CSD

[Olivier Fourdan <fourdan gmail com>]

Hi all,


I am not one of them, but there are a lot of people (including KDE
devs apparently) concerned about CSD because it means different
decorations depending on the apps/toolkit => Consistency might suffer.

Currently, it's up to the apps/toolkits to tell the WM they want to
remain undecorated (via Motif MWM hints) so that they can manage their
decorations themselves. GTK+ can optionally use CSD for its dialogs as
well via a specific setting.

I would like to evaluate a different approach, the opposite way
actually, instead of the apps deciding to go with CSD or SSD, it would
be up to the DE to set a hint telling the apps if they /should/ prefer
CSD or SSD. The DE /may/ expose that option to the user (or not), up
to the DE devs to decide.

I think it's very little change in GTK+ as it's already able to do
both SSD and CSD (currently, decision to use CSD or SSD being made at
run time based on the availability of a compositor).

gnome-shell (or any other WM) would just have to set the relevant hint
to tell the apps to prefer CSD. Apps that cannot or don't know how to
do CSD would still be decorated, just like now => The final word still
remains to the applications, just like now.

Since GTK+ has different backends for Wayland or Mir, those would
remain unaffected (and still prefer CSD, unless someone wants to add a
similar mechanism for Wayland - /me looks at KDE).

I am willing to work on patches for that on my spare time (I do expect
these to be minimal), but before I spend some time on this, I'd like
to evaluate the chances of such an idea to be accepted... Was this
already discussed in the past maybe?

Cheers,
Olivier