Private Sub RichTextBox1_MouseDown(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles RichTextBox1.MouseDown
        If e.Button = MouseButtons.Right Then
            Dim c As New ContextMenu
            For i As Integer = 0 To 9
                Dim x As New MenuItem(i)
                c.MenuItems.Add(x)
            Next
            c.Show(RichTextBox1, New Point(e.X, e.Y))
        End If
    End Sub