The Linux world is slowly but surely moving towards Wayland as a replacement for X11. At some point we need to be able to natively support this brave new world. It does have legacy support for X11 applications though, so we are not completely excluded from that world.
Note that Wayland explicitly hides global coordinates from windows. This can cause problems coordinating monitor placement between tlclient and vncviewer. See bug 7793 for some details.