First I would like to say that I enjoy working with your program. It has a lot of abilities and flexibilities. But I notice that is not so robust as it should be. The worst thing what can happen to the user is when you lose the drawing that you were working on it for few hours. It occurred to me. When I try to open the file, I am getting a message (Load from Stream Failed, Error Message: Object reference not set to an instance of an object). Your Autosave option is not helpful as well. First I do not know when Autosave puts the files second what happens when the file still does not have a name, where autosave puts the backups.