"Incoming call popup" is a small windows that shows caller information such as last call, location of caller (city/country level) and operator on top of any windows. If you find it not useful and want to disable it, please follow below steps
- Open Blacklist app
- Click on 3-dot button, then Settings
- Click on "Call" (first row)
- Click on "Incoming call popup", then select other position OR "Do not show" to disable.