Feathers
The Starling version is no longer under active development. Future work will be focused on the new OpenFL version of Feathers UI.
Note: Technically, a Haxe and OpenFL version of Starling is available, but new Feathers UI development will focus on the pure OpenFL version (which is on the classic display list and doesn't integrate Starling anymore). If you'd like to keep using Starling and Feathers together, but switch from AS3 to Haxe, community member Matse has recently ported the original Starling version of Feathers to Haxe.
Get started with Feathers, the open source library of user interface components for the hardware-accelerated Starling Framework. A robust skinning system enables your creativity, fluid layouts make it easy to deploy to a variety of screens, and support for both touch and mouse interaction puts your apps on mobile and desktop. With Feathers and Starling, you can build fully-standalone native apps for iOS, Android, Windows, and macOS, and you can even deploy to desktop web browsers with Adobe Flash Player.