I think that the behavior is going to depend on many factors including your platform (Unix/Linux/Windows), terminal emulator settings, and installed software. For example, I can do this with the screen program (screen _progres) on a Solaris box but I don't have success with screen on Linux. Vi preserves the screen on the Linux box I tested but not on the Solaris box. Windows is a different beast entirely and I think we would have to implement support for this in _progres.exe for it to work on Windows.
I should have mentioned I'm using putty (TERM=xterm) on a rhel linux box.
invisible-island.net/.../ctlseqs.html
\E[2J clears the screen.
But playing around with putty and protermcap I don't see any obvious way to get _progres to leave the contents of the session on the screen. It might be my imagination but _progres seems to deliberately clear all frames before exiting.