How to split the screen to use 2 apps simultaneously?

[Martin 0]

When I swipe from the Home button to the left and then click on the app icon, then there is no menu with the option of split screen. Instead, the app window just turns white. That's all it does. Could you please help me how to fix this?

[Hook 3,020]

5 minutes ago, Martin said:

When I swipe from the Home button to the left and then click on the app icon, then there is no menu with the option of split screen. Instead, the app window just turns white. That's all it does. Could you please help me how to fix this?

A little more information would be helpful.  Do you have a Pro 1 or Pro1x?  I am assuming you are using either Android or LineageOS. 

If I assume you are using a Pro1x with stock Android 11, start both apps you want to use for split screen.  Go to recents (for me that would be pressing the square as I don't use gestures-- I don't know what the gesture for recents is), press and hold on the first app you want.  A menu will pop up. Tap split screen,  Then tap the app recent for the second app.  Not al that intuitive (or flexible) but how Android works it.

I actually don't remember if the Pro 1's stock Android 9 works that way it has been sop long since I had stock on my Pro 1.