rem: this.mOutliner.appendChild(col); 
add: cols.appendChild(col); 
context:   buildColumns: function()  {    var cols = this.mColumns;    var col, val, split;    for (var i = 0; i < cols.length; i++) {      col = document.createElementNS(kXULNSURI, "outlinercol");      col.setAttribute("id", "outlinercol-"+cols[i].name);      col.setAttribute("persist", "width");      col.setAttribute("label", cols[i].title);      // mark first node as primary, if necessary      if (i == 0 && this.mIsContainer)        col.setAttribute("primary", "true");      val = cols[i].className;      if (val)        col.setAttribute("class", val);      val = cols[i].flex;      if (val)        col.setAttribute("flex", val);      this.mOutliner.appendChild(col);      if (this.mSplitters && i < cols.length-1) {        split = document.createElementNS(kXULNSURI, "splitter");        split.setAttribute("class", "tree-splitter");        this.mOutliner.appendChild(split);      }    }  },
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/949278c0feae623ad87fbb837a26296fb734c13e/inTreeBuilder.js/clean/extensions/inspector/resources/content/jsutil/xul/inTreeBuilder.js