You control the basic structure of your application by specifying the order in which frames can be opened and by controlling which frames run concurrently with others.

Unlike a terminal‑based environment in which the end user can work with only one frame at a time, a window-based environment lets the end user work with any number of active frames. An active frame is a frame that has the input focus and that end users can work in. Users can click the mouse in the frame, select menu or button operations, or enter data. They can also reposition the frame on the screen. For more information about making a frame the active frame, see the FrameExec class topic in the Language Reference Guide.

As you design an application, you should consider how the end user will proceed when moving sequentially from one frame to another when the user can work with more than one frame at a time. For a description of common structures for an OpenROAD application, see Controlling the Flow of Frames.