rem: var kids = aItem.getElementsByTagName("treechildren"); if (kids.length == 0) { kids = document.createElement("treechildren"); aItem.appendChild(kids); 
add: var treechildren = aItem.getElementsByTagName("treechildren").item(0); if (!treechildren) { treechildren = document.createElement("treechildren"); aItem.appendChild(treechildren); 
context:   openTreeItem: function(aItem)  {    var kids = aItem.getElementsByTagName("treechildren");    if (kids.length == 0) {      kids = document.createElement("treechildren");      aItem.appendChild(kids);    }        this.buildPropertyTree(kids, aItem.__JSValue__);  },
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/27be36a7f8826d6252caf8409c0d6b6dfda7d7c1/jsObjectViewer.js/buggy/extensions/inspector/resources/content/viewers/jsObject/jsObjectViewer.js