Update (11 Oct. 2015): As suggested by xperiacle over at xda, changing ro.build.type to userdebug might interfere with other functions of the device. A better way to enable multi-window on Marshmallow would be to simply add persist.sys.debug.multi_window=true to build.prop. See the instructions below for details.

Android 6.0 Marshmallow has more features than it shows. Like the System UI Tuner which let’s you customize Quick settings panel and Status bar icons, there’s another hidden feature on Marshmallow that let’s you view multiple apps together in a split view.

Marshmallow has this new feature that Samsung’s Galaxy devices have had for years — Multi Window. However, Google meant this feature for Android tablets only, you can’t enable it on your Nexus 5, Nexus 6 or any other phone running on Marshmallow.

But if you’re rooted, there’s a workaround to get multi-window on your phone as well. You just need to make a simple change to the build.prop file on your device and it’ll have multi-window activated.

Below are full instructions to get multi-window on Marshmallow:

  1. Get root. If you’ve a Nexus phone, follow this guide — How to Root Android 6.0 Marshmallow.
  2. Download and install a file manager app with root access from Play Store (we prefer ES File Explorer).
  3. Open your file manager app and grant it root permission.
  4. Now go to /system/ directory and open the build.prop file to edit it.
  5. Inside build.prop file, add the following line to the end (or anywhere) and save the file: 
    persist.sys.debug.multi_window=true
  6. Reboot device.
  7. Once rebooted, go to Settings » About phone » tap Build number seven times to enable “Developer options”.
  8. Go back to Settings » select Developer options » enable Multi-window from the list of options.

That’s it. This should get Multi Window on your Nexus 5, Nexus 6 and other Android phones running Android 6.0 Marshmallow. You can access/use it from the recent apps screen.

Happy Androiding!