In E4 we are trying to address some of the main pain points RCP-Application developers faced – Their application looks like Eclipse and the theming/presentation API is not flexible enough to modify all aspects of the UI (e.g. Toolbar/MenuBar, …)!
The first step to make your application look different was that we introduced the concept of declarative styleing (CSS).
But like in other aspects E4 goes further and allows you to exchange complete widgets like the application-shell, the menu and toolbar, the Stack-Folders (the standard theme uses CTabFolder) resulting in an E4-Demo-Application like this:
You want to know more about how this works and how the internals of the workbench make such things possible? Then I’d suggest to you attend the EcliseCon-talk about the modeled workbench Boris and I are delivering at EclipseCon09
But E4 goes even further! It allows you to plugin every widget-technology you want to! The internals don’t care whether your application gets renderered by QT, Swing, UFaceKit you name it. So I’ve done that and here’s my UFaceKit-Demo-Application built on top of E4:
Makeing UFaceKit a possible renderer of E4 opens the doors to all technologies supported by UFaceKit (Swing, QT, GWT, …) and its advanced DeclartiveStyling-Support