Fixed bug 1526 - X11 - XUnmapWindow should not be called directly

driedfruit

In X11_HideWindow, we call XUnmapWindow to unmap. According to ICCCN2.0, this should never happen, and XWithdrawWindow should be called instead.

http://www.tronche.com/gui/x/icccm/sec-4.html#s-4.1.4

"The reason for requiring the client to send a synthetic UnmapNotify event is to ensure that the window manager gets some notification of the client's desire to change state, ***even though the window may already be unmapped when the desire is expressed***."

Additionally, this can be observed at http://cgit.freedesktop.org/xorg/lib/libX11/tree/src/Withdraw.c#n65

Failure to comply leads to "MapNotify" event never appearing on non-reparenting WMs after subsequent show-hide-show requests. (I'm currently observing this behavior, thus my bug report).