A dialog item is a child window of the dialog window, which usually is a window of class WC_FRAME. The operating system provides many predefined window classes, called control windows, that you can use as dialog items. Predefined control windows include static display boxes, text-entry fields, buttons, and list boxes. You also can use customized window classes as dialog items.
Dialog items are windows and, thus, can be manipulated by all window-management functions relating to size, position, and visibility. Dialog items always are owned by the dialog frame window. Most predefined control-window classes send notification messages to their owners when the user interacts with their control windows. The dialog frame window receives these notification messages and passes them to the application through the application-defined dialog procedure.