Usually, there is a blue line on the border of the split screens that allows me to adjust the window size of the split screen. However, for some reason, the line has disappeared and I am unable to adjust the split screen size.
We request you to please follow these below steps and check again.
Power off >> Press and hold volume up key + power button >> Samsung logo >> release finger >> use the volume down button >> wipe cache partition >> click power button >> Yes >> Reboot.
I recommend you to turn off your device by holding power button and volume down button together and turn on. I did this and when i opened it again issue was fixed.
