Protected Overrides Sub OnMouseUp(ByVal mevent As _
     System.Windows.Forms.MouseEventArgs)
      Dim selStart As Integer = GetFirstIndexOfPart()
      Dim selLength As Integer = GetLengthOfPart()
 
      If Me.SelectionStart <> selStart Then Me.SelectionStart = selStart
      If Me.SelectionLength <> selLength Then Me.SelectionLength = selLength
 
      MyBase.OnMouseUp(mevent)
   End Sub