Private Sub Button1_MouseDown(ByVal sender As System.Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles Button1.MouseDown
        CheckBox1.Checked = True
    End Sub
 
    Private Sub Button1_MouseUp(ByVal sender As System.Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles Button1.MouseUp
        CheckBox1.Checked = False
    End Sub