detect() didn't check if _XGrDisplay is already open.
I'm not sure how relevant this is, my plans are to replace the partially working vd_xwin and it's problematic xfdga counterpart with vd_sdl, which will (as of -rc3) support fullscreen/windowed via GRX20DRV= ::fs and ::ww and have an ugly and incomplete Win~1 fullscreen backup/restore.