Menu: Ignore bubbled mouseenter events on parent items

Test uses QUnit 2.x API - inconsistent with the other tests, but also a good reference. Fixes #11641 Closes jquerygh-1535

Author: jzaefferer

tests/unit/menu/menu_events.js

@@ -111,6 +111,48 @@ asyncTest( "handle focus of menu with active item", function() {
 });
 });
 
+test( "handle mouseenter on nested menu item", function( assert ) {
+assert.expect( 8 );
+$.ui.menu.prototype.delay = 1;
+var activeItem,
+done = assert.async(),
+element = $( "#menu2" ).menu();
+
+element
+.menu( "previous" )
+.menu( "expand" );
+
+function checkSubmenus() {
+equal( element.find( "ul[aria-expanded='true']" ).length, 2, "both submenus expanded" );
+}
+function menumouseenter1() {
+element.menu( "expand" );
+setTimeout( menumouseenter2, 25 );
+}
+function menumouseenter2() {
+checkSubmenus();
+activeItem = $( "#" + element.attr( "aria-activedescendant" ) );
+assert.hasClasses( activeItem, "ui-state-active" );
+activeItem.trigger( "mouseleave" );
+setTimeout( menumouseenter3, 25 );
+}
+function menumouseenter3() {
+checkSubmenus();
+assert.lacksClasses( activeItem, "ui-state-active" );
+activeItem.trigger( "mouseenter" );
+setTimeout( menumouseenter4, 25 );
+}
+function menumouseenter4() {
+checkSubmenus();
+activeItem.parents( ".ui-menu-item" ).each( function( index, item ) {
+assert.hasClasses( $( item ).children( ".ui-menu-item-wrapper" ), "ui-state-active" );
+} );
+$.ui.menu.prototype.delay = 300;
+done();
+}
+setTimeout( menumouseenter1, 25 );
+} );
+
 asyncTest( "handle submenu auto collapse: mouseleave, default markup", function() {
 expect( 4 );
 $.ui.menu.prototype.delay = 1;

ui/menu.js

@@ -108,13 +108,22 @@ return $.widget( "ui.menu", {
 }
 },
 "mouseenter .ui-menu-item": function( event ) {
+
 // Ignore mouse events while typeahead is active, see #10458.
 // Prevents focusing the wrong item when typeahead causes a scroll while the mouse
 // is over an item in the menu
 if ( this.previousFilter ) {
 return;
 }
-var target = $( event.currentTarget );
+
+var actualTarget = $( event.target ).closest( ".ui-menu-item" ),
+target = $( event.currentTarget );
+
+// Ignore bubbled events on parent items, see #11641
+if ( actualTarget[ 0 ] !== target[ 0 ] ) {
+return;
+}
+
 // Remove ui-state-active class from siblings of the newly focused menu item
 // to avoid a jump caused by adjacent elements both having a class with a border
 this._removeClass( target.siblings().children( ".ui-state-active" ),