rem: expandedNode = document.getElementById("expandedHeaderView"); collapsedNode = document.getElementById("collapsedHeaderView"); 
add: var expandedNode = document.getElementById("expandedHeaderView"); var collapsedNode = document.getElementById("collapsedHeaderView"); 
context: function ToggleHeaderView (){  expandedNode = document.getElementById("expandedHeaderView");  collapsedNode = document.getElementById("collapsedHeaderView");  if (gCollapsedHeaderViewMode)  {              gCollapsedHeaderViewMode = false;    // hide the current view    hideHeaderView(gCollapsedHeaderView);    // update the current view    updateHeaderViews();        // now uncollapse / collapse the right views    expandedNode.removeAttribute("collapsed");    collapsedNode.setAttribute("collapsed", "true");  }  else  {    gCollapsedHeaderViewMode = true;    // hide the current view    hideHeaderView(gExpandedHeaderView);    // update the current view    updateHeaderViews();        // now uncollapse / collapse the right views    collapsedNode.removeAttribute("collapsed");    expandedNode.setAttribute("collapsed", "true");  }  }
meta: 5459	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5459/f7ab7fe212a77ea2ffd7b7aa9f47b7f21c70170f/msgHdrViewOverlay.js/clean/mailnews/base/resources/content/msgHdrViewOverlay.js