The decorative frame and title bar (possibly including buttons) that is usually seen around windows are created by the window manager, not by the client that creates the window. The window manager also handles input related to these elements, such as resizing the window when the user clicks and drags the window frame. Clients usually operate on the window they created disregarding the changes operated by the window manager. A change it has to take into account is that re-parenting window managers, which almost all modern window managers are, change the parent of top-level windows to a window that is not the root. From the point of view of the core protocol, the window manager is a client, not different from the other applications.