I am a little confused as to the issue. Is it the overlay won't turn off or is it something involving your build app? If the former, I am including info on turning it off below. If it is the latter, then I would need more information.
How to Disable Screen Overlay
Here are a few things you can try to turn it off.
Option 1
1. Go to "Setting", then "Developer Option"
2. Now go to "Simulate Secondory Display" and tap "off" or "None".
Option 2
1. Go to "Setting", then "More".
2. Tap "About Device".
3. Go to "Build Number" and tap it "7 times".
4. This should turn off "developer options".
5. The overlays should disappear.
Option 3
If you have the app "Clean Master" on your phone.
1. Open "Clean Master" and then tap "Settings".
2...