The Timer Handler

    private void timer1_Tick(object sender, System.EventArgs e)

    {

      if(opening & closerPos!=45)

        closerPos++;

      if(!opening & closerPos!=0)

        closerPos--;

      if(closerPos==0 | closerPos==45)

        this.timer1.Enabled=false;

      CreateWindowRegion();

      Invalidate();

    }

  }

    Private Sub timer1_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles timer1.Tick

      If opening And closerPos <> 45 Then

        closerPos += 1

      End If

      If Not opening And closerPos <> 0 Then

        closerPos -= 1

      End If

      If closerPos = 0 Or closerPos = 45 Then

        Me.timer1.Enabled = False

      End If

      CreateWindowRegion()

      Invalidate()

    End Sub 'timer1_Tick