Related issues here. I do not have a title bar on QGC 4.1.4 (Windows 10). Another computer with the same version of Windows and QGC has the title bar, but I can’t figure out how to get it on the other system. What is the proper way to exit QGC without the title bar with the “X”? I’ve always been puzzled by that with QGC on all platforms. Why isn’t there an obvious way to quit the application or switch between full-screen and windowed modes?
Thank you.
I’m not sure how I did it, but I now have QGC running in a window on one of my Panasonic ToughPads with min, max, and close buttons as usual for a windows application. I believe it’s related to device rotation. I will update as I investigate further.
Got it…sort of. 
I could not reproduce the switch from full screen to windowed mode…BUT I found where to make manual edits to the QGroundControl.ini to force different window states.
This is related to: QGC window opening at saved screen coordinates even if they become invalid · Issue #9202 · mavlink/qgroundcontrol · GitHub
The QGroundControl settings file is located (Windows):
C:\Users\<me>\AppData\Roaming\QGroundControl.org\QGroundControl.ini
The section of concern is:
[MainWindowState]
visibility=x
The “x” values the best I can tell are:
1 = Nothing, resets to “2”
2 = Normal window
3 = Minimized window
4 = Maximized window
5 = Full Screen no window borders and no min, max, or close buttons
The question remains: How to you exit QGC if the application is running full screen with no window borders or buttons?
Have you been able to find a way to close QGC? Like you, I use a ToughPad and have not been able to find a way to close the application.
On a computer with a physical keyboard, you can press ALT+F4.
It may also be possible to use a 3rd party app assigned to the A1 or A2 button to forcefully close QGC or issue a close event (as if the X button was pressed). I was however hoping for a proper close option via QGC.