[[the question of how an application can force some part of itself as the top level window is a FAQ]]

Could someone please write something here about the topic?

ptk*

'''Win32'''

  SetWindowPos(HWND hWnd,       // handle to window
               HWND hWndAfter,  // placement order handle
               int x, int y,    // position (horizontal, vertical)
               int cx, int cy,  // size (width, height) 
               UINT uFlags)     // positioning flags
The placement order handle can be either another HWND or once of the following constants:
    HWND_BOTTOM 1 Moves to the bottom
    HWND_NOTOPMOST -2 Place above all non-topmost windows.
    HWND_TOP 0 Move to the top
    HWND_TOPMOST -1 Move to the top and keep it there.