Since there's no manual so found this only by accident, so yes it's secret lol!!
Slide finger from right to left of screen...
The brightness part is cool to have there, hate messing with that stiupid slide up thing on I phone, always takes a couple tries and end up pressing things in app by accident!
The Rev Posted at 2017-3-8 09:21
I think it does but you have to be connected to your Mavic at the time.
Next time you are flying try and swipe from the right
I tried it once more while connected to the Mavic and it worked. Disconnected and it still worked. Force unloaded all Apps and restarted Go4 and now it still works.