Of the many interesting features of the Android M Developer preview, one that wasn’t talked about at all was Multi Window.
Apparently the feature is only available if you have rooted Android M and edited the build.prop file which is something Android looks at upon boot. Once the feature is enabled though, that’s where the fun starts. Multi Window on Android M is different than it is on Samsung devices but at least it’s going to be available in stock Android now.
Of course Multi Window needs more work and I’m hopeful that it would at least appear in Developer Options in the 2nd preview release coming in late June/early July and be available for everyone in the final build.