Only show top-level items when adding pages to a User's First Nav Menu. (This is also the title of Dave's first children's book.)

props lessbloat.
fixes #25122.

Built from https://develop.svn.wordpress.org/trunk@25622


git-svn-id: http://core.svn.wordpress.org/trunk@25539 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/js/nav-menu.js

@@ -178,6 +178,11 @@ var wpNavMenu;
 							var t = $(this),
 								listItemDBIDMatch = re.exec( t.attr('name') ),
 								listItemDBID = 'undefined' == typeof listItemDBIDMatch[1] ? 0 : parseInt(listItemDBIDMatch[1], 10);
+							
+							// Only show top level items
+							if (0 !== t.closest('ul.children').length)
+								return;
+							
 							if ( this.className && -1 != this.className.indexOf('add-to-top') )
 								processMethod = api.addMenuItemToTop;
 							menuItems[listItemDBID] = t.closest('li').getItemData( 'add-menu-item', listItemDBID );