That's very odd. We've raised this issue with the Sencha Desktop Packager team and neither of our teams have been able to reproduce the issue. If you are able to find a way to reproduce it please let us know so that we can get it resolved.Mucking around with this further - I quit Architect, relaunched it. In the opening dialogue (recent projects) there is a fullscreen toggle button. I tapped that, and then loaded my project. Lo and behold, the fullscreen button now appears in the menu and I can unfullscreen the app. I've tried to recreate the bug of the disappearing full screen button but haven't yet.