May be, this topic doesn’t want to disable camera control by gamepad in viewport.
Slate.EnableGamepadEditorNavigation = false
Try to use this console command.
I can disable editor control (ex. change menu focus by gamepad left stick) by gamepad.
This parameter is initialized when editor restart.
So, if you want to disable it always, add this text to DefaultEngine.ini:
[ConsoleVariables]
Slate.EnableGamepadEditorNavigation = false