How to enable multi-window mode in Android 6.0 Marshmallow

Update: In a recent Reddit Ask Me Anything, Andrew from the Pixel C team at Google confirmed that native multi-window support is coming in Android N, which will be previewed at Google I/O 2016 and released later in the year when the two new Nexus devices come out.

All you need to do is change a single field in "ro.build.type". / © ANDROIDPIT

Prerequisites

• A rooted phone running Android 6.0 Marshmallow
• A root file manager with text editor (like ES File Explorer) or Build Prop Editor

Build Prop Editor

How to enable multi-window mode on Android 6.0 Marshmallow

1. Open Build Prop Editor and scroll down to ro.build.type. Tap it and change the Property Value from user to userdebug.
2. Tap Save and then Yes to reboot your phone (this is necessary to apply the changes).

Change the Property Value to "userdebug", save your changes and reboot. / © ANDROIDPIT

3. Once you've rebooted, go to Settings > Developer options > Multi-window mode and flip the switch. (If you don't already have Developer options enabled, go to Settings > About phone and tap Build number seven times until you see the notification.)

Once you've edited the build.prop file, multi-window mode appears in Developer Options. / © ANDROIDPIT

Using multi-window mode on Android 6.0 Marshmallow

In your multi-tasking view (or recent apps list), you'll now see a square bracket in the upper right of each app card. Tap the target to choose the split-screen view you want: upper half, lower half or full screen. Note that top and bottom switch to left and right in landscape mode.

You now have multi-window capabilities in Marshmallow. / © ANDROIDPIT

Once you've chosen your split-screen preference, the app will always appear in that view. So, for example, if you've chosen YouTube in top-half view then tapping YouTube in the multi-tasking list will always bring it up in the top half. If you want to go full screen you'll have to select that by tapping the square bracket in the top right of the app card again.