It is annoing that I can't use anymore long-press button to split a screen - which was more than much easier version than the newer version.
Also what I've noticed is that I can not close used programs one-by-one. If I want to close example just only one program, then actually I have to close all the programs.
Why the hell to ruin something that works more than wonderfully?!?!?!?!?!?!?!?!
If you have an app like tiktok that cannot be used in multi view or split screen on Samsung s9, Here is an option to fix that for android 9.0 and 10.
Samsung S9 G960u android 9.0 pie
You can use every app including tiktok your S9 in split screen and pop up view by changing one setting in developer options and installing 2 apps from the Galaxy Store made by Samsung electronics.
In developer options, scroll all the way down, the second option from the bottom: "Force activities to be resizable:
Make all activities resizable formulti-window, regardless of manifest values" find this option and turn it on.
Now download Good Lock by samsung from the Galaxy Store. Once you open the app "Good Lock" find multistar and load that app from the galaxy store also.
Now inside the "Good Lock" app you will be able to access multistar. Inside multistar make sure to turn on these 3 options or only the ones you need are on.
1.Use Multi window without pausing: no pausing of videos or activities while using multiple at once.
2.Enable multi window to all apps: All apps can be launched in a Popup window
and split screen. The app may not work
3.Pop-up view action: When an app is open in full screen, switch to a pop-up view by swiping down diagonally from either corner at the top of the screen
Now after your phone restarts you should have split screen options enabled on all apps and pop-up view on most. Pop-up view does work on EVERY app if you use pop-up view action, even though the option isn't available the normal way this still works (switch to a pop-up view by swiping down diagonally from either corner at the top of the screen)
Galaxy store links: Goodlock- http://apps.samsung.com/appquery/appDetail.as?appId=com.samsung.android.goodlock
(Turning on Developer options:
Go to your Samsung S9 and Open Settings option.
Under Settings option, select About phone, then choose Software Information.
Scroll down the screen and tap Build number several times until you see a message that says “Developer mode has been enabled”.
Select on the Back button and you will see the Developer options menu under Settings)
Tested on S9 running 9.0
Galaxy store says the apps are compatible with android 10.
An Update to Good Lock that applys to android 10 users
In the "Good Lock" app by Samsung under multistar you can reactivate the feature to long press an app and open it in split or pop up view