Application window is not refreshing correctly in the VNC based on xinetd with XDMCP sessions

Issue

• GNOME desktop sessions that usage VNC based on xinetd with XDMCP are not usable with the tigervnc-server-minimal-1.8.0-13.el7 package.
• When a user try to change the tabs in the applications eg: Firefox, or type something in GNOME-terminal, or open the GNOME-terminal menu, the screen is usually not refreshing (or partially refreshing).
• The problem is reproducible with any other X11 application. The problem started with latest version of tigervnc-server-minimal package. The issue also exists when using thetigervnc-server backend with XRDP.