rem: return Components.classes[ progId ].createInstance( iid ); 
add: return Components.classes[ contractId ].createInstance( iid ); 
context:     createInstance : function ( progId, iidName ) {        var iid = Components.interfaces[ iidName ];        return Components.classes[ progId ].createInstance( iid );    },
meta: 8395	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/8395/0257791053c2b38e1dfaf2ee11afae973e82e394/nsContextMenu.js/buggy/xpfe/browser/resources/content/nsContextMenu.js