The following classes provide support for windows:
- _U_MENUorID Provides wrappers for CreateWindow and CreateWindowEx. 
- CWindow Contains methods for manipulating a window. CWindow is the base class for CWindowImpl, CDialogImpl, and CContainedWindow. 
- CWindowImpl Implements a window based on a new window class. Also allows you to subclass or superclass the window. 
- CDialogImpl Implements a dialog box. 
- CAxDialogImpl Implements a dialog box (modal or modeless) that hosts ActiveX controls. 
- CSimpleDialog Implements a dialog box (modal or modeless) with basic functionality. 
- CAxWindow Manipulates a window that hosts an ActiveX control. 
- CAxWindow2T Provides methods for manipulating a window that hosts an ActiveX control and also has support for hosting licensed ActiveX controls. 
- CContainedWindowT Implements a window contained within another object. 
- CWndClassInfo Manages the information of a new window class. 
- CDynamicChain Supports dynamic chaining of message maps. 
- CMessageMap Allows an object to expose its message maps to other objects. 
- CWinTraits Provides a simple method of standardizing the traits of an ATL window object. 
- CWinTraitsOR Provides default values for window styles and extended styles used to create a window. These values are added, using the logical-OR operator, to values provided during the creation of a window.