This chapter describes how your application can use the Control Manager to create and manage controls.
Controls are onscreen objects that the user can manipulate with the mouse.
By manipulating controls, the user can take an immediate action or change settings to modify a future action. For example, a scroll bar control allows a user to immediately change the portion of the document that your application displays, whereas a pop-up menu control for baud rate might allow the user to change the rate by which your application handles subsequent data transmissions. Read this chapter to learn how and when to implement controls. Virtually all applications need to implement controls, at least in the form of scroll bars for document windows. You use Control Manager routines, resources, and data structures to implement scroll bars in your application's document windows.