sub setup_menu 
{
  my ($top) = @_;
  my $menubar = $top->Menu();
  $top->configure(-menu => $menubar);
  my $input = $menubar=>Menubutton (
                                   -text => 'File',                              -menuitems => [Button => 'load xml', -command => sub {$user_xml = $menubar->getOpenFile();}]
      );