An overlapped window is a top-level window that is meant to serve as an application's main window. It can also have a command bar, task bars, and scroll bars. An overlapped window used as a main window typically includes all of these components. An application creates an overlapped window by specifying the WS_OVERLAPPED or WS_OVERLAPPEDWINDOW style in the CreateWindowEx function.
Because many Windows CE-based devices have small screens, you should use the full screen for your primary window. To accommodate different screen sizes, use either the dimensions returned by the GetSystemMetrics function to define the size of your primary window or specify CW_USEDEFAULT in the nWidth and nHeight parameters that you send to CreateWindow or CreateWindowEx.
The qualities of an application window depend on the platform for which it was designed. For Windows CE-based platforms that support graphical user interfaces, a typical application window may include a command bar, a client area, and a vertical scroll bar.
The command bar is a Windows CE toolbar that can contain menus, controls, and separators. An application's command bar typically contains a menu bar as well as a Close (X) button, a Help (?) button, and an OK button. Windows CE does not support the Maximize or Minimize buttons found in Windows-based desktop platforms.
Items on the menu bar represent the main categories of commands. Choosing an item on the menu bar typically opens a pop-up menu whose items correspond to the tasks within a specified category. By choosing a command, the user directs the application to carry out a task. In Windows CE, menu bars are always contained within command bars; Windows CE does not support stand-alone menu bars.
Note In Windows CE, the command bar is considered part of the client area.
A pop-up window is a special type of overlapped window used for dialog boxes, message boxes, and other temporary windows that appear outside an application's main window. Title bars are optional for pop-up windows; otherwise, pop-up windows are the same as overlapped windows of the WS_OVERLAPPED style.
You create a pop-up window by specifying the WS_POPUP style in CreateWindowEx. To include a title bar, specify the WS_CAPTION style.