function flipflop(obj) {
	// find the first sibling of the heading, that was clicked
	var li = obj.nextSibling;
	// make sure we'll find an actual element, and not some text
	// or a comment or something else (comments, in MY code?)
	while (li.nodeType != document.ELEMENT_NODE) {
		li = li.nextSibling;
	}
	
	var dis = "none";
	obj.style.listStyleImage = "url('flip.png')";
	// if the element we found is already hidden, show it.
	if (li.style.display == "none") {
		dis = "block";
		obj.style.listStyleImage = "url('flop.png')";
	}
	
	// while we have more sibings
	while (li != null) {
		// if we have an element-node
		if (li.nodeType == document.ELEMENT_NODE) {
			li.style.display = dis;
		}
		// proceed to the next sibling
		li = li.nextSibling;
	}
}