Paul and Wengier,
The U2 screen sync works by reading the COLS= and LINS= values from the relevant config file (i.e., the file pointed to by environment variable VDOSP_CONFIG). It sets the XyWrite default SW to the COLS value and default SL to the LINS value. It's a one-time thing that occurs (unless the user has disabled it) at startup, so I doubt that it could be a factor in the problem that Paul is seeing, which happens later, when he shells to DOS. In fact, commanding VDOSSYNC<Helpkey> may help by reinstating the desired screen dimensions after returning from DOS -- though this begs the question of what's causing this weird anomaly in the first place.