Index: wp-admin/js/postbox.js
===================================================================
--- wp-admin/js/postbox.js	(revision 22467)
+++ wp-admin/js/postbox.js	(working copy)
@@ -105,7 +105,7 @@
 
 		save_state : function(page) {
 			var closed = $('.postbox').filter('.closed').map(function() { return this.id; }).get().join(','),
-				hidden = $('.postbox').filter(':hidden').map(function() { return this.id; }).get().join(',');
+				hidden = $('.hide-postbox-tog').not(':checked').map(function() { return this.value; }).get().join(',');
 
 			$.post(ajaxurl, {
 				action: 'closed-postboxes',