Why do the speakerphone and hang up buttons disappear on my s9 when i'm on speakerphone?

[Android Central Question]

I often need to look at my s9 phone's calendar or some other screen when I'm on a call. I put the call on speakerphone and navigate to the appropriate screen. When I go back to the screen with the dial pad, both the speakerphone button and the hang up button have disappeared. So I have to finish the call on speakerphone, and must wait for the other person to hang up. Please help. This did not happen with my s6 or any previous phone.

 

[methodman89]

Have you tried to clear the cache partition and reboot? If you double tap the recent app button, would it bring it back correct?

 

[lucianus_luciferus]

It could be the theme you are using. Try switching to the default theme and see it if happens again.