How do I run a application on top, in a display manager like GDM.(RHEL 7, Gnome 3.8.4
 

I want to show keyboard layout and selection of language at login screen in RHEL 7.

I have modified the language menu to show "show keyboard layout" and "Region & Language settings".
On clicking above menu items, applications are launched but they are not visible at login screen.
I check the programs are running by taking a remote session.

gkbd-keyboard-display -l us
gnome-control-center region

above two applications are executing but none is displaying at login screen(gdm).

How can I bring the applications at top of display manager(gdm).

I have tried