Bug fix and comments to Util.mouseLeft().

git-svn-id: http://svn.openlayers.org/trunk/openlayers@307 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Util.js

@@ -758,9 +758,12 @@ OpenLayers.Util.getTagText = function (parent, item, index) {
 * @return {boolean}
 */
 OpenLayers.Util.mouseLeft = function (evt, div) {
+    // start with the element to which the mouse has moved
     var target = (evt.relatedTarget) ? evt.relatedTarget : evt.toElement;
-    while (target != div && target.nodeName != 'BODY') {
+    // walk up the DOM tree.
+    while (target != div && target != document.documentElement) {
         target = target.parentNode;
     }
-    return (target == div);
+    // if the target we stop at isn't the div, then we've left the div.
+    return (target != div);
 };