For another interesting GUI concept... (Score 2, Interesting)

... take a look at ENIÄK. It intends to bring a logically structured framework to GUIs such as HTML is to the Web or LaTeX to publishing; granted, it's been stalling for a long time due to the main developer having other things to do, but the concept is fascinating: imagine no longer needing to think about the concrete graphical layout, widget sets etc. when developing the interface for an application. Imagine just defining it in the sense of determining the logical hierarchy of elements: windows, text entry points, buttons, menus -- anything conceptually different from another element. And forget about the layout: the (yet unproven) goal of the architecture is that just as LaTeX automatically positions your document so that it is as readable and good-looking as possible, ENIÄK would automatically position and render the elements of the UI to create an optimal user interface.

Many other advantages can be derived from the user interface not being defined physically but conceptually:

• Platform-independence: the architecture relies on a general display server which translates the conceptual elements into a particular interface format, be it Windows, OSX, Gtk or HTML. The application's interface specification, however, remains the same for all platforms. In other words, once a display server exists for a particular platform, all ENIÄK applications will work on it.
• I/O format independence: deriving from the previous point, display servers can equally well be created for text-only console displays or PDAs.
• Lightweight remote use: since the interface is specified based on its logical structure, very little data needs to be transferred from an application to its display server. After this, the (local) display server takes care of rendering, and all that's transferred between it and the (remote) application are lightweight event descriptions.

OK, enough advocation. Problems do still exist with the concept, mainly a) it's not compatible with any existing application and b) there's no proof of concept until a sufficiently advanced display server is created that actually shows some indication of that the server can adequately automate the process of transformation from a logical, structured interface description into an intuitive, user-friendly physical interface. There's a long way to go, but still, I can't help but to be fascinated by such a concept of abstraction. For more info, read the white paper or complete specification