Private Const WM_MOUSEMOVE As Int32 = &H200
    Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
        If m.Msg = WM_MOUSEMOVE AndAlso _
            m.WParam.ToInt32 = 1 AndAlso _
            Me.SelectionLength > 1 Then Return
        MyBase.WndProc(m)
    End Sub