rem: if (item == null) return null; 
context:     getDropTarget: function(event) {        var item = tw_getEventTarget(event, "treeRow");        if (item == null) return null;        return this._fullIndex(item);    },
meta: 5515	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5515/cfa7cacc22cf44240d4fdac2a16ac0b70fe21708/Tree.js/buggy/src/thinwire/render/web/resources/Tree.js