use php\lang\System;
    use php\swing\UIForm;
    use php\swing\UICombobox;
    use php\swing\event\ItemEvent;

    $form = new UIForm();
    $form->size = [500, 500];
    $form->moveToCenter();
    $form->on('windowClosing', function(){
        System::halt(0);
    });

    $menu = ['open' => ['o1' => 'out1','o2' => 'out2','o3' => 'out3','o4' => 'out4'],
	     'save' => ['s1' => 'out5','s2' => 'out6','s3' => 'out7','s4' => 'out8'] ];


    $c = new UICombobox();
    $c->size = [100, 25];
    $c->position = [150, 100];
    $c->setItems($menu['open']);
    $c->on('change', function(ItemEvent $e) use ($menu,$form,$c){
        if ($e->isSelected()) {
        $form->title = $menu['open'][$c->getItem($c->selectedIndex)];
       }
    });

    $form->add($c);

    $form->visible = true;