only prevent event from falling through if there are actually listeners registered. this fixes #247

git-svn-id: http://svn.openlayers.org/trunk/openlayers@1423 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Events.js

@@ -1,7 +1,7 @@
 /* Copyright (c) 2006 MetaCarta, Inc., published under the BSD license.
  * See http://svn.openlayers.org/trunk/openlayers/license.txt for the full
  * text of the license. */
- 
+
 /**
  * @class
  */
@@ -159,7 +159,7 @@ OpenLayers.Events.prototype = {
 
         // execute all callbacks registered for specified type
         var listeners = this.listeners[type];
-        if (listeners != null) {
+        if ((listeners != null) && (listeners.length > 0)) {
             for (var i = 0; i < listeners.length; i++) {
                 var callback = listeners[i];
                 var continueChain;