Index: wp-admin/js/common.js
===================================================================
--- wp-admin/js/common.js	(revision 24974)
+++ wp-admin/js/common.js	(working copy)
@@ -185,15 +185,15 @@
 			if ( body.hasClass('auto-fold') ) {
 				body.removeClass('auto-fold').removeClass('folded');
 				setUserSetting('unfold', 1);
-				deleteUserSetting('mfold');
+				setUserSetting('mfold', 'o');
 			} else {
 				body.addClass('auto-fold');
-				deleteUserSetting('unfold');
+				setUserSetting('unfold', 0);
 			}
 		} else {
 			if ( body.hasClass('folded') ) {
 				body.removeClass('folded');
-				deleteUserSetting('mfold');
+				setUserSetting('mfold', 'o');
 			} else {
 				body.addClass('folded');
 				setUserSetting('mfold', 'f');