changing the display gnome-shell is syncing to on the fly

[Belegdol]

Hi,

as described in detail here, gnome shell needs to have __GL_SYNC_DISPLAY_DEVICE=DFP-2 set not to tear on the DVI monitor. My question is, is it possible to change this on the fly, perhaps using nv-control, or perhaps restart gnome-shell in a way it does not lose session features like gnome-keyring. Running

$ __GL_SYNC_DISPLAY_DEVICE=DFP-2 gnome-shell --replace --display=:0

kills the tearing, but then "dissociates" gnome shell from the session. On the other hand, if you press alt-f2 and press r <enter>, shell will restart without that drawback, but I can't pass environmental variable. Is there a way of getting around this?