Index: src/event.js
===================================================================
--- src/event.js	(revision 3830)
+++ src/event.js	(working copy)
@@ -195,7 +195,8 @@
 
 		// Namespaced event handlers
 		var parts = event.type.split(".");
-		event.type = parts[0];
+		if (parts[1])
+			event.type = parts[0];
 
 		var handlers = jQuery.data(this, "events") && jQuery.data(this, "events")[event.type], args = Array.prototype.slice.call( arguments, 1 );
 		args.unshift( event );
@@ -233,7 +234,11 @@
 		// store a copy of the original event object 
 		// and clone to set read-only properties
 		var originalEvent = event;
-		event = jQuery.extend({}, originalEvent);
+		var F = function () {};
+		F.prototype = originalEvent;
+		event = new F();
+		if (!event.type)
+			event = jQuery.extend({}, originalEvent);
 		
 		// add preventDefault and stopPropagation since 
 		// they will not work on the clone