Re: Menu windows appear in window manager windows list ?

[Truls Becken]

On Nov 22, 2007 11:28 AM, Fred Kiefer <fredkiefer@gmx.de> wrote:
> > I see from xprop that _NET_WM_STATE is not set on the menus. How about
> > setting that to _NET_WM_STATE_SKIP_TASKBAR and
> > _NET_WM_STATE_SKIP_PAGER ? My panel does this in addition to
> > _NET_WM_WINDOW_TYPE_DOCK.
> >
>
> We already have code that should be doing exactly this in place in
> XGServerWindow.m, starting line 3152. Most likely I did get the
> specification wrong and it isn't sufficient to send a message, we also
> have to set the property. In the other places where I call sendRoot: we
> already do this.
>
> Anybody willing to write a patch for this?
> Some simple XChangeProperty() with add and remove should be enough.

I gave this a shot, but could not get it to work correctly. The
following observations were made:

1) The net_wm_state hint needs to be set every time the window is
about to be displayed. I open TextEdit and the main menu has
skip_taskbar and skip_pager set. Switching to xterm and back to
TextEdit, and the state hint has been cleared. The first time I open
the Document menu, skip_taskbar and pager are set. Second time it is
opened the hint is cleared. Reading the EWMH spec reveals that this is
actually correct behavior for this particular hint:

http://standards.freedesktop.org/wm-spec/wm-spec-1.4.html#id2511406

"The Window Manager should remove the property whenever a window is
withdrawn, but it should leave the property in place when it is
shutting down, e.g. in response to losing ownership of the WM_Sn
manager selection.

Rationale: Removing the property upon window withdrawal helps legacy
applications which want to reuse withdrawn windows. Not removing the
property upon shutdown allows the next Window Manager to restore
windows to their previous state. "

2) For some odd reason that I was not able to figure out, the actual
document windows in TextEdit get skip_taskbar and skip_pager set, even
though they are window_type_normal. The code is supposedly not setting
up that combination.

3) OpenBox includes the net_wm_window_type_menu windows in the alt-tab
ring even when they do have skip_taskbar/pager set, but it leaves them
out of the window list (middle click on desktop) - until the issue in
1) kicks in of course. The net_wm_window_type_normal windows OTOH are
excluded from alt-tab while the skip flags are set. Oh, the joy.

I made an attempt at setting net_wm_state when windows are re-mapped
by simply removing an if statement in -setwindowlevel. This did make
the hint stick, but also introduced a weird situation where xprop
sometimes gave results like:

_NET_WM_STATE(ATOM) = _NET_WM_STATE_ADD, _NET_WM_STATE_SKIP_TASKBAR,
_NET_WM_STATE_SKIP_PAGER, PRIMARY
or:
_NET_WM_STATE(ATOM) = _NET_WM_STATE_REMOVE,
_NET_WM_STATE_SKIP_TASKBAR, _NET_WM_STATE_SKIP_PAGER, PRIMARY

on windows that stick around for longer periods, i.e. the ones that
are not unmapped when the application looses focus. This urged me to
try to only use net_wm_state_skip_taskbar and net_wm_state_skip_pager
as data, but this somehow only set skip_taskbar, and it was cleared
again on window unmap. I also tried using PropModeAppend without much
success. Note that PropModeReplace might even be wrong for this hint
since the window manager adds state info such as shaded, maximized,
sticky, below, etc.

Attached is a patch that adds the XChangeProperty() call. It also adds
three atoms to XGWMNetStates, which I assumed was the proper way for
frequently used atoms. The attempt to repeatedly set the hint is in
the second file. Alas, neither of these are any good. It seems that
successfully applying the net_wm_state hint requires quite a bit more
work, and a different hint is probably necessary to skip the alt-tab
cycle on some window managers.

Truls

net_wm_state.diff
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net_wm_state2.diff
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