Samsuns S10+. Weird divider and split circle in full screen.

[antonavy]

Hey, everyone!
I'm not really sure what happened, but my phone started showing this weird looking divider when I'm watching a full screen video (youtube, netflix, etc).
I installed a couple of extra launchers, gave up some permissions (e.g. for gesture apps).
Tried to restrict "appear on top" permissions, doesn't seem to help.
Please, help me get rid of that annoyance

 

[antonavy]

Wasn't logged in. Here's the screenshot.

 

[mustang7757]

Hi, welcome to AC!

[Moved this to s10 forums for specific traffic]

 

[B. Diddy]

Welcome to Android Central! What happens if you tap the circle, or swipe up or sideways from it?

Or maybe it's just telling you that you can't do split screen while watching a video in fullscreen?

Do you happen to be using Multistar, a Good Lock feature?

I changed the post owner of the OP of this thread to you, to make it easier for you to find.