No middle-click on GNOME app title bar in KDE

[Francois Gouget <fgouget@free.fr>]

So I have configured KDE to send a window to the background when I 
middle click in its title bar [1]. But when I do on the 'title bar' of a 
GNOME application (e.g. Gedit) nothing happens. [2]

My understanding is that this is because GNOME applications don't have a 
window manager-controlled title bar. Instead they have an 
application-controlled "header bar" with a hardcoded behavior that does 
not match the KDE configuration. [3]

BUT...

A right-click in the "header bars" brings up a different menu depending 
on whether the GNOME application is running in GNOME or in KDE. So they 
are somehow aware of the environment they are in and appear to be able 
to adapt to it.

The content of the right-click menu still does not match the one I get 
when right-clicking on a real title bar.

So on the one hand GNOME header bars seem to be able to adapt to the 
desktop environment they are in, but on the other hand they still don't 
match it.

Is it because I misconfigured something? Is there a special package that 
needs to be installed to let GNOME applications better integrate with 
KDE?

SO...

Do I have discrepencies because KDE never provided the required support? 
Or is it that GNOME applications lack the support for integrating with 
any environment besides GNOME? (and revert to a hardcoded default 
behavior in such cases)



[1] System Settings -> Window Management -> Window Behavior -> Titlebar 
    actions -> Titlebar and Frame Actions -> Middle click -> Lower.

[2] In GNOME a middle-click on a GNOME header bar is treated as a 
    left-click, that is it raises the window. But the same action on a 
    GNOME header bar in KDE gives focus the first time, and raises it 
    the second time. So if the window is already raised and has the 
    focus nothing happens.

[3] In fact one can configure Mutter so a middle-click lowers the 
    window:
      gsettings set org.gnome.desktop.wm.preferences \
                    action-middle-click-titlebar 'lower'
      (set to 'none' for the default behavior)
    But this only works on real window manager-controlled title bars. So 
    it works on KDE's Konsole for instance, but not on GNOME's own GNOME 
    Terminal or Gedit!

-- 
Francois Gouget <fgouget@free.fr>              http://fgouget.free.fr/
            You don't liberate a people. A people liberates itself.
                                   Youssoupha