just tested in lucid.
on pluging in an external monitor, and pressing detect monitor, the new display is detected, and the screen spans across it. compiz seems to automatically fall back to metacity. apart from loss of desktop effects everything carries on working. no crash.
if i run glxgears, and then resize its window, after it passes a certain width the display of the gears is corrupted. but there is no crash.
just tested in lucid.
on pluging in an external monitor, and pressing detect monitor, the new display is detected, and the screen spans across it. compiz seems to automatically fall back to metacity. apart from loss of desktop effects everything carries on working. no crash.
if i run glxgears, and then resize its window, after it passes a certain width the display of the gears is corrupted. but there is no crash.
seems that the freeze is fixed for me