anchor.diff:    TfpgListBoxStrings = class(TStringList)
     protected
       ListBox: TfpgTextListBox;
  -    procedure   SetUpdateState(Updating: Boolean); override;
     public
       constructor Create(AListBox: TfpgTextListBox);
       destructor  Destroy; override;
  
positive.code: procedure TfpgListBoxStrings.Clear;
  begin
    inherited Clear;
    ListBox.FocusItem := -1;
    ListBox.UpdateScrollBar;
    ListBox.Invalidate;
  
negative.code: 
  { TfpgListBoxStrings }
  
  constructor TfpgListBoxStrings.Create(AListBox: TfpgTextListBox);
  begin
    inherited Create;
  