[vb6] Enable Form move anywhere

If a form has a title bar, the user can move it by pressing the left mouse button on the title bar and then move the window. However, if the form doesn't have a title bar, it cannot be moved. The sub listed below enables movement of a form, irrespective of its style. Typically, you would call this sub when the user presses the left mouse button on the form and possibly also when he presses the same button on contained controls. The sub works by faking a WM_NCLBUTTONDOWN message to be sent to the form window procedure.

    Private Const HTCAPTION& = 2
    Private Const WM_NCLBUTTONDOWN& = &HA1
    Private Declare Function SendMessageBynum& Lib "user32" _
        Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, _
        ByVal wParam As Long, ByVal lParam As Long)
    Private Declare Function ReleaseCapture& Lib "user32" ()
    
    Public Sub StartMove(frm As Form)
      ReleaseCapture
      SendMessageBynum frm.hwnd, WM_NCLBUTTONDOWN, HTCAPTION, 0
    End Sub