You may need to enable Multi Window in the Settings menu in order to use the feature. Follow the instructions below:
1. Turn on the OnePlus 3
2. Go to the Settings menu
3. Go to the Multi window under Device
4. In the the top right corner of the screen, switch the toggle Multi window to On
5. Select if you want the content in Multi Window mode by default by checking the box next to Open in multi window view
After you have enabled Multi Window Mode on the OnePlus 3, check to see that you have a grey semi or half circle on the screen. This half circle or semi circle on the OnePlus 3 screen means that you have enabled the settings and you’re ready to start using the Multi Window Mode.
To start using this feature, you need to tap the semicircle with your finger to bring multi window to the top. After you have done this, drag the icons from the menu to the window you want it to open in. A great feature on the OnePlus 3 is the ability to resize the window by pressing and holding the circle in the middle of the screen and placing it to the new location you want it to go.
