add:  tree.appendChild(document.createElement('treechildren')); 
context: function save_initial_panels(){  var tree = document.getElementById('current-panels');  if (!tree.view) {    setTimeout(save_initial_panels, 0);  } else {    for (var i = 0; i < tree.view.rowCount; ++i) {      var item = tree.contentView.getItemAtIndex(i);      original_panels.push(item.id);    }  }}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/d2e394719cd8ffeca25e35cddfaa7364f7e7be17/customize.js/buggy/xpfe/components/sidebar/resources/customize.js