So, like I said in the title...my Thunderbird minimizes to the tray, and every time I open it from the tray, it isn't opened full screen...maximized. It is restored down....like when you press that middle button, left from the X. I don't know it is called, it says Restore down when you hover it. I'm using the latest x64 bit version, and my OS is Win10 Pro. Let me just say, that it happens only if I leave my PC for a longer period of time, couple of hour and it goes to sleep. Once it's awaken, opening Thunderbird is not the issue anymore. Only the first time. Any ideas?