anchor.diff:  
   procedure TfpgTabSheet.SetPageControl(APageControl: TfpgPageControl);
   begin
  -   FPageControl:=APageControl;
  -   if APageControl <> nil then
  +  FPageControl := APageControl;
  +  if APageControl <> nil then
       FPageControl.InsertPage(Self);
   end;
   
  
positive.code:   Result := FPages.Count;
  end;
  
  procedure TfpgPageControl.InsertPage(const APage: TfpgTabSheet);
  begin
    if FPages.IndexOf(APage) <> -1 then
      Exit; //==>   The page has already been added.
    FPages.Add(APage);
    { TODO: This behaviour could maybe be controlled by a Options property }
    if FPages.Count=1 then
      ActivePage := APage;
  end;
  
  procedure TfpgPageControl.RemovePage(const APage: TfpgTabSheet);
  
negative.code:   if (AOwner <> nil) and (AOwner is TfpgPageControl) then
    begin
      FPageControl:=TfpgPageControl(AOwner);  
      FPageControl.InsertPage(self, True);
    end;
  end;
  
  