The user directs input data to windows from a mouse and the keyboard. Keyboard input goes to the window with input focus, and, normally, mouse input goes to the window under the mouse pointer.
Windows also are places to display output data. PM uses windows to display text and graphics on the screen and to process input from the mouse and keyboard. Windows provide the same input and output capabilities as a virtual graphics terminal without having direct control of the hardware.
An application is responsible for painting the data for the window classes it registers and creates. This data can be graphics text or pictures or fixed-size alphanumeric text. Normally it is not necessary for the application to paint the system-provided window classes; the OS/2 window procedures for those window classes do the painting.