Be compliant with EWMH standard that states: "If _NET_WM_WINDOW_TYPE is not...

Be compliant with EWMH standard that states: "If _NET_WM_WINDOW_TYPE is not set, then windows with WM_TRANSIENT_FOR set MUST be taken as NET_WM_WINDOW_TYPE_DIALOG". It shouldn't make much difference in xfwm4 though.


(Old svn revision: 25920)