Unblock PreRender's scrambling & solving oonly AFTER we change screen to READ post-scrambling (otherwise it was possible to press the 'solve' button in the brief period between unblocking and switching screen because switching screen runs on the background UI thread)
Unblock PreRender's scrambling & solving oonly AFTER we change screen to READ post-scrambling (otherwise it was possible to press the 'solve' button in the brief period between unblocking and switching screen because switching screen runs on the background UI thread)