Index: src/js/_enqueues/admin/common.js
===================================================================
--- src/js/_enqueues/admin/common.js	(revision 51882)
+++ src/js/_enqueues/admin/common.js	(working copy)
@@ -854,7 +854,7 @@
 		// Reset any compensation for submenus near the bottom of the screen.
 		$('#adminmenu div.wp-submenu').css('margin-top', '');
 
-		if ( viewportWidth < 960 ) {
+		if ( viewportWidth <= 960 ) {
 			if ( $body.hasClass('auto-fold') ) {
 				$body.removeClass('auto-fold').removeClass('folded');
 				setUserSetting('unfold', 1);