procedure TForm12.tree1Change(Sender: TObject; Node: TTreeNode);
begin try
hint:='';
FlatButton2.Enabled :=(Node.ImageIndex =20);
FlatButton1.Enabled := FlatButton2.Enabled;
if Node.ImageIndex =20 then begin
   tree1.PopupMenu := self.PopupMenu1 ;
   hint:=url_.Strings[ref_.IndexOf(Node.Text)];
end else
   tree1.PopupMenu:=nil;
except end;End;