Widget: Don't use $.event.props when creating events.

(cherry picked from commit 91ef69d)

ui/jquery.ui.widget.js

@@ -239,28 +239,28 @@ $.Widget.prototype = {
 	},
 
 	_trigger: function( type, event, data ) {
-		var callback = this.options[ type ];
+		var prop, orig,
+			callback = this.options[ type ];
 
+		data = data || {};
 		event = $.Event( event );
 		event.type = ( type === this.widgetEventPrefix ?
 			type :
 			this.widgetEventPrefix + type ).toLowerCase();
-		data = data || {};
+		// the original event may come from any element
+		// so we need to reset the target on the new event
+		event.target = this.element[ 0 ];
 
 		// copy original event properties over to the new event
-		// this would happen if we could call $.event.fix instead of $.Event
-		// but we don't have a way to force an event to be fixed multiple times
-		if ( event.originalEvent ) {
-			for ( var i = $.event.props.length, prop; i; ) {
-				prop = $.event.props[ --i ];
-				event[ prop ] = event.originalEvent[ prop ];
+		orig = event.originalEvent;
+		if ( orig ) {
+			for ( prop in orig ) {
+				if ( !( prop in event ) ) {
+					event[ prop ] = orig[ prop ];
+				}
 			}
 		}
 
-		// the original event may come from any element
-		// so we need to reset the target on the new event
-		event.target = this.element[0];
-
 		this.element.trigger( event, data );
 
 		return !( $.isFunction(callback) &&