Just like in other phone manufacturers, they actually wait for the app developers to support and enable within their apps the multiscreen functionality. With the current update, 5.1.60G, I have noticed Facebook, Instagram, Chrome, Wechat, Youtube, Google Maps, Google Photos, Google Translate, ShareIt, VLC, and Spotify to have multiscreen functionalities, in addition to Settings and Videos. So far, those are the only apps I tried as they are the only ones I had installed with multiscreen support. :)

Skype, Twitter, and Google Play Music is also in the mix. :)

That's also the problem in Samsung and LG's multiscreen support. Not all app developers and even the manufacturer's own apps are multiscreen capable. However, compared to others, I see more 3rd party apps in Meizu than in other Brands that support multiscreen. To name a few, I am amazed that spotify and instagram can do that. :)