Context menu

I’m trying to implement the context menu following the online example… But, the menu doesn’t appear. Instead, the browser’s context menu appears.

   menu = new dhtmlXMenuObject();
    menu.setIconsPath('../../Content/Images/dhtmlx/dhxmenu_dhx_skyblue/');
    menu.renderAsContextMenu();
    menu.attachEvent("onClick", function (menuitemId, type) {

//do something
});
menu.loadXML(“…/…/Content/ContextMenu.xml”);

    tree.enableContextMenu(menu);

Any idea why?