Does _NET_WM_STATE_HIDDEN imply _NET_WM_STATE_SKIP_TASKBAR

Question

After switching from KDE to XFCE, I notice that the boinc manager window will remain visible in the task bar as a minimized window when I close the window. On KDE (as far as I remember), closing the window had the effect of completely hiding it, while a system tray icon remained to control the application. I guess that's the intended behavior in any case.

According to xprop, the window has

WM_STATE(WM_STATE):
                window state: Iconic
                icon window: 0x10a3f90
_NET_WM_STATE(ATOM) = _NET_WM_STATE_HIDDEN

The state atom _NET_WM_STATE_SKIP_TASKBAR which would explicitely indicate omission from the task bar is not included in that list.

Now I want to figure out where to correct this. Should I fix xfce-panel to skip windows which have hidden state? Or should I try make the window state include _NET_WM_STATE_SKIP_TASKBAR? The code path for the hiding the window appears to be via wxWidgets and its wxWindowGTK::Show method to gtk_widget_hide to XWithdrawWindow, so perhaps xfwm4 should react and add that atom?

Are there any official documentations of how hiding a window is supposed to work?

Answer 1

_NET_WM_STATE_HIDDEN should be set by the window manager, not the application. In particular, all minimized windows should have _NET_WM_STATE set to _NET_WM_STATE_HIDDEN. By no means does this state imply _NET_WM_STATE_SKIP_TASKBAR.