Fix opening closed widget areas when dragging a widget over them.

Props polevaultweb. Fixes #13524.

git-svn-id: https://develop.svn.wordpress.org/trunk@33088 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/js/widgets.js

@@ -128,7 +128,7 @@ wpWidgets = {
 		 * Opens and closes previously closed Sidebars when Widgets are dragged over/out of them.
 		 */
 		sidebars.droppable( {
-			tolerance: 'pointer',
+			tolerance: 'intersect',
 
 			/**
 			 * Open Sidebar when a Widget gets dragged over it.
@@ -146,6 +146,7 @@ wpWidgets = {
 				if ( $wrap.hasClass( 'closed' ) ) {
 					wpWidgets.hoveredSidebar = $wrap;
 					$wrap.removeClass( 'closed' );
+					sidebars.sortable( 'refresh' );
 				}
 			},
 
@@ -169,6 +170,7 @@ wpWidgets = {
 			distance: 2,
 			containment: '#wpwrap',
 			tolerance: 'pointer',
+			refreshPositions: true,
 			start: function( event, ui ) {
 				var height, $this = $(this),
 					$wrap = $this.parent(),