Index: wp-admin/js/common.js
===================================================================
--- wp-admin/js/common.js	(revision 23621)
+++ wp-admin/js/common.js	(working copy)
@@ -174,24 +174,12 @@
 		// reset any compensation for submenus near the bottom of the screen
 		$('#adminmenu div.wp-submenu').css('margin-top', '');
 
-		if ( $(window).width() < 900 ) {
-			if ( body.hasClass('auto-fold') ) {
-				body.removeClass('auto-fold');
-				setUserSetting('unfold', 1);
-				body.removeClass('folded');
-				deleteUserSetting('mfold');
-			} else {
-				body.addClass('auto-fold');
-				deleteUserSetting('unfold');
-			}
+		if ( body.hasClass('folded') ) {
+			body.removeClass('folded');
+			deleteUserSetting('mfold');
 		} else {
-			if ( body.hasClass('folded') ) {
-				body.removeClass('folded');
-				deleteUserSetting('mfold');
-			} else {
-				body.addClass('folded');
-				setUserSetting('mfold', 'f');
-			}
+			body.addClass('folded');
+			setUserSetting('mfold', 'f');
 		}
 	});
 
Index: wp-admin/admin-header.php
===================================================================
--- wp-admin/admin-header.php	(revision 23621)
+++ wp-admin/admin-header.php	(working copy)
@@ -71,8 +71,7 @@
 if ( get_user_setting('mfold') == 'f' )
 	$admin_body_class .= ' folded';
 
-if ( !get_user_setting('unfold') )
-	$admin_body_class .= ' auto-fold';
+$admin_body_class .= ' auto-fold';
 
 if ( is_admin_bar_showing() )
 	$admin_body_class .= ' admin-bar';