Widgets screen: while dragging a widget over a closed sidebar refresh only the widgets in the current sidebar instead of all widgets in all sidebars.

Props chriscct7. Fixes #33015.
Built from https://develop.svn.wordpress.org/trunk@33354


git-svn-id: http://core.svn.wordpress.org/trunk@33326 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/js/widgets.js

@@ -146,8 +146,9 @@ wpWidgets = {
 				if ( $wrap.hasClass( 'closed' ) ) {
 					wpWidgets.hoveredSidebar = $wrap;
 					$wrap.removeClass( 'closed' );
-					sidebars.sortable( 'refresh' );
 				}
+
+				$( this ).sortable( 'refresh' );
 			},
 
 			/**