http://www.xulplanet.com/tutorials/xultu/morelists.html http://www.xulplanet.com/reference/elemref/ref_listhead.html A header row of a listbox. It is usual to place listheader elements inside the listhead, one for each column. Indicates whether the listhead is disabled or not. If this attribute is set to true, the listhead is disabled. This is usually drawn with the text in grey. If the listhead is disabled, it does not respond to user actions. The element cannot be focused and the command event will not fire. The element will still respond to mouse events. To enable the listhead, leave the attribute out entirely as opposed to setting the value to false.