работа с TreeView

TreeView.Items.AddChild(TreeView.Selected, 'Узел');

TreeView.Selected.Delete;

procedure TreeToIni(Tree: TTreeView; INI: TIniFile; Section: string);
var
  n: Integer;
  MS: TMemoryStream;
  tTv: TStringList;
  Msg: string;
begin
  tTv := TStringList.Create;
  MS := TMemoryStream.Create;
  try
    Tree.SaveToStream(MS);
    MS.Position := 0;
    tTv.LoadFromStream(MS);
    INI.EraseSection(Section);
    for n := 0 to tTv.Count - 1 do
      INI.WriteString(Section, 'Node' + IntToStr(n), StringReplace(tTv[n], #9,
        '#', [rfReplaceAll]));
  finally
    tTv.Free;
    MS.Free;
  end;
end;

var
  tn: TTreeNode;
begin
  tn:=TreeView.Items.AddChild(TreeView.Selected, 'Узел');
  tn.Selected:=true;
end;

TreeView.HideSelection:=false;

var
  tn: TTreeNode;
begin
  tn:=TreeView.Items.AddChild(TreeView.Selected, 'Узел');
  tn.Selected:=true;
  TreeView.SetFocus; // это помогло
end;