How do you get a new text message notification to pop up as a window smaller than full size?

[Halpmepl0x]

Hi, there were a couple of times where I have received a text message (both times playing a game in portrait) and was able to reply through a window that is about 60% the size of your full screen. I'm not sure how I did it and the reason I find this convenient is that I dont have to minimize my game and my game is actually still running in the background. My game was full screen and my text window was about 60% of full screen placed exactly in the center. If you think of the game as a rectangle well there was a smaller rectangle for the text message right in the middle.

I know this is kind of confusing as I'm new to these forums and don't see where I can attach a picture. Any help is appreciated. Also I'm using a galaxy s8.

 

[methodman89]

Can't you adjust the priority of the message so it only alerts without appearing on the screen?