A GUI is a collection of elements with specific look and behaviour. A Desktop Environment is a collection of GUI(s), tools and services. Native means you have s

A GUI is a collection of elements with specific look and behaviour. A Desktop Environment is a collection of GUI(s), tools and services. Native means you have something which follows this look and behaviour 100% and can utilize all the tools and services. Implementing the look is simple, adding behaviour quite harder and utilizing the service the endgame. WebUI usually does nothing from those or some parts, it all depends on the constellation. But usually there is a obvious difference at some point where you realize whether something is native or just made an attempt.