Samsung Galaxy Note 4 - Manual (Page 62)

Motions & usability features
62
Moving or closing pop-up windows
To move a pop-up window, tap the circle on a window and drag it to a new location.
To close the window, tap the circle at the top of the window and tap .
Launching pop-up windows from the split screen Multi window
1
On the split screen Multi window, tap an app window to launch it in a pop-up window.
2
Tap and hold the circle between the app windows.
The selected app will launch in a pop-up window.
Launching pop-up windows from the Multi window tray
Tap and hold to open the Multi window tray. Tap an app icon in the Multi window tray to
launch it in a pop-up window.
If Multi window is not activated, open the All apps screen, tap Settings → Multi
window, and then tap the Multi window switch to activate it. Alternatively, open the
quick settings panel and tap Multi window to activate it.