Because every control is a child window, it requires a parent window. You specify the parent window when creating the control, by including the handle of the parent window in the hWndParent parameter of the CreateWindow function.
As with any child window, a control is affected by changes to its parent window. For example, if Windows disables the parent window, it also disables the control. If Windows paints, moves, or destroys the parent window, it also paints, moves, or destroys the control.
Although a control can be any size and can be moved to any position, it is restricted to the client area of the parent window. Windows clips the control if you move it outside the parent window's client area or make it larger than the client area.