My app was rejected because of this
As far as I understand this button appears if the app started right from the TestFlight. If you start the app by clicking on the app icon this button doesn't show up. I also noticed that at the development time when I cick F5 in B4i the same...
I have a toolbar on the bottom of the screen in my app. It's visible in Debug mode. When I uploaded my app to the iTuneConnect and open it on the same iPhone in TestFlight the toolbar is missing.
Now my app was approved for sale, I installed it on my phone - the toolbar is missing.