gnome-shell: stray configure notify event
When unmapping X11 client, Gnome sends a stray configure notify event, where 'y' has been moved up by the height of the window decoration. Originally reported here: https://bugreports.qt.io/browse/QTBUG-71671
From xtrace output I see that gnome re-parents the window to the root window and mistakenly adjusts 'y' coordinate. There are no plausible reasons why WM should change window's coordinates when unmapping. KWin, Mate, XFce doesn't do that.
000:>:01c6: Event (generated) ConfigureNotify(22) event=0x02a00005 window=0x02a00005 above-sibling=None(0x00000000) x=600 y=526 width=200 height=200 border-width=0 override-redirect=false(0x00) 000:>:01c6: Event ReparentNotify(21) event=0x02a00005 window=0x02a00005 parent=0x0000011b x=600 y=526 override-redirect=false(0x00)
root window id = 0x0000011b 0x02a00005 = window which coordinates before calling unmap are x=600, y=600
To get more details about my env and package versions see https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1804467