Most of our system tools we keep in windows to give them a little more structure. This creates a SystemWindow Morph and sets the model to be the WorkspacePane that we just created. Remember back to our WorkspacePane menu. When you pull up a menu when the WorkspacePane is in a SystemWindow, the SystemWindow tells its model to put up the menu appropriate to the model. Shifted which provides the standard text editing menus.
Some models are very complicated.
Most of the time though they just provide some glue to keep things together, and a place to share common data between Morphs. In this example, it lets the SystemWindow talk to the WorkspacePane. The layout is reponsible for keeping each pane in an assigned location when the window is resized. The points represent where you want the Morph placed inside the window on a relative scale of 0.0 to 1.0 . That's how the Browsers and other multi-panel windows keep their layouts straight, they have a little map which guides their placement in the window.