add: if (!buttons.firstChild) {  chevron.collapsed = true; return; }  
context:   resizeFunc: function(event)   {     var buttons = document.getElementById("bookmarks-ptf");    if (!buttons)      return;    var chevron = document.getElementById("bookmarks-chevron");    chevron.collapsed = false;    var chevronWidth = chevron.boxObject.width;    chevron.collapsed = true;    var remainingWidth = buttons.boxObject.width;    var overflowed = false;    for (var i=0; i<buttons.childNodes.length; i++) {      var button = buttons.childNodes[i];      button.collapsed = overflowed;            if (i == buttons.childNodes.length - 1)        chevronWidth = 0;      remainingWidth -= button.boxObject.width;      if (remainingWidth < chevronWidth) {        overflowed = true;        // This button doesn't fit. Show it in the menu. Hide it in the toolbar.        if (!button.collapsed)          button.collapsed = true;        if (chevron.collapsed) {          chevron.collapsed = false;        }      }    }    BookmarksToolbarRDFObserver._overflowTimerInEffect = false;  },
meta: 8395	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/8395/d4ad872168d66597c8f806ddf546b07523f5e35e/bookmarksMenu.js/clean/xpfe/components/bookmarks/resources/bookmarksMenu.js