The applications launched in the XDMCP session are showing the black window.

Issue

• When a user try to launch any application(Eg: Firefox, GNOME-Terminal and GNOME-Control-Center etc..) in the XDMCP session, the application windows is complete black.
• Every GUI application is showing same behaviour in the XDMCP session.
• The problem is reproducible only when the user connects to the RHEL7.6 system via xdmcp from the other system in the network.