Widgets: Toggle widget arrow when widget is open/closed.

props MikeHansenMe.
fixes #26748.
Built from https://develop.svn.wordpress.org/trunk@28235


git-svn-id: http://core.svn.wordpress.org/trunk@28063 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/css/common-rtl.css

@@ -2270,7 +2270,8 @@ img {
 
 .control-section.open .accordion-section-title:after,
 #customize-info.open .accordion-section-title:after,
-.nav-menus-php .menu-item-edit-active .item-edit:before {
+.nav-menus-php .menu-item-edit-active .item-edit:before,
+.widget.open .widget-top a.widget-action:after {
 	content: '\f142';
 }
 

wp-admin/css/common.css

@@ -2270,7 +2270,8 @@ img {
 
 .control-section.open .accordion-section-title:after,
 #customize-info.open .accordion-section-title:after,
-.nav-menus-php .menu-item-edit-active .item-edit:before {
+.nav-menus-php .menu-item-edit-active .item-edit:before,
+.widget.open .widget-top a.widget-action:after {
 	content: '\f142';
 }
 

wp-admin/js/widgets.js

@@ -50,10 +50,12 @@ wpWidgets = {
 						css[ margin ] = widgetWidth - ( targetWidth + 30 ) + 'px';
 						widget.css( css );
 					}
+					widget.addClass( 'open' );
 					inside.slideDown('fast');
 				} else {
 					inside.slideUp('fast', function() {
 						widget.attr( 'style', '' );
+						widget.removeClass( 'open' );
 					});
 				}
 				e.preventDefault();