Widget: Only use the event prefix from the base if we're redefining a widget. Fixes #8805 - Widget: widgetEventPrefix is incorrect when inheriting with jQuery UI 1.9.1.

(cherry picked from commit 9e858ba)

Author: scottgonzalez

tests/unit/widget/widget_core.js

@@ -332,8 +332,8 @@ test( "re-init", function() {
 	deepEqual( actions, [ "optionfoo", "init" ], "correct methods called on re-init with options" );
 });
 
-test( "inheritance - options", function() {
-	expect( 4 );
+test( "inheritance", function() {
+	expect( 6 );
 	// #5830 - Widget: Using inheritance overwrites the base classes options
 	$.widget( "ui.testWidgetBase", {
 		options: {
@@ -354,13 +354,17 @@ test( "inheritance - options", function() {
 		}
 	});
 
+	equal( $.ui.testWidgetBase.prototype.widgetEventPrefix, "testWidgetBase",
+		"base class event prefix" );
 	deepEqual( $.ui.testWidgetBase.prototype.options.obj, {
 		key1: "foo",
 		key2: "bar"
 	}, "base class option object not overridden");
 	deepEqual( $.ui.testWidgetBase.prototype.options.arr, [ "testing" ],
 		"base class option array not overridden");
 
+	equal( $.ui.testWidgetExtension.prototype.widgetEventPrefix, "testWidgetExtension",
+		"extension class event prefix" );
 	deepEqual( $.ui.testWidgetExtension.prototype.options.obj, {
 		key1: "baz",
 		key2: "bar"

ui/jquery.ui.widget.js

@@ -101,7 +101,7 @@ $.widget = function( name, base, prototype ) {
 		// TODO: remove support for widgetEventPrefix
 		// always use the name + a colon as the prefix, e.g., draggable:start
 		// don't prefix for widgets that aren't DOM-based
-		widgetEventPrefix: basePrototype.widgetEventPrefix || name
+		widgetEventPrefix: existingConstructor ? basePrototype.widgetEventPrefix : name
 	}, prototype, {
 		constructor: constructor,
 		namespace: namespace,