For some window managers (fvwm2 and fvwm3) if the X server isn't
running and has output it's possible for the window manager to fail or
reconfigure randr incorrectly.
With xrdp-waitfox:
- Install xrdp-waitfox to the BIN dir.
- sesman will run xrdp-waitfox as the logged in user.
- Set an alarm to exit after 30 seconds.
- Try to open env DISPLAY value's display (10 seconds).
- Test for RandR extension.
- Wait for outputs to appear (10 seconds).