Setting a recommended framework for UI libraries

In simplifying the Window Server API, the control framework makes a number of design decisions that are optimised for most applications. For example, redraw events are handled at a lower priority than user input events. This is part of the way in which it imposes a recommended framework for applications, but there are other aspects.

One is the framework's concept of controls, which are similar to windows, but which may be only part of a window. Although from the programmer’s point of view the distinction between windows and controls offers no advantage in terms of simplicity, it allows applications much greater run-time efficiency.

Another feature of the control framework is the support it provides for handling key events. In the Window Server, only applications, and not individual windows, can have keyboard focus: the application itself is responsible for channelling key presses to the appropriate window. The framework provides support for channelling key presses to different controls within an application.