This removes the window rect checks that were there to unmap visible windows when they are outside of the virtual screen. Since the recent changes to window config update, and the removal of WindowPosChanged re-entry guards, we now more accurately match the states between win32, winex11 and X server and it caused some windows to now be unmapped spuriously. This happens when the window manager positions the outside of what we believe is the virtual screen, for instance with embedded or FVWM virtual desktops.
I am not sure what unmapping offscreen windows is for exactly, I suspect it is to allow some windows to be moved offscreen even though the WM would probably not allow it with visible windows. I think that if windows are managed by the host WM, we should allow it to control and constraint the windows to be on-screen if it decides so. Alternatively we could perhaps decide to minimize them instead (as a winex11 internal state, without notifying the Win32 side of minimization), as unmapping the windows will also make them disappear from the window selector, and makes it impossible to focus them back.