Hello I had this same problem and it is stupid they don't make it possible to turn of the button..

But working on it a lot. I found a solution!

Download a random app from playstore (one you don't need) then go to setting and change the button to open that app the test that it works and then delete the app and the button does nothing ;)

Good luck

I had this same problem, and found a solution!

Download a random app (one that you don't actually need) from Play Store, then go to Settings (Personal / Xcover key) and change the button to open that app. Test that it works, and then delete the app, and now the button does nothing. ;)