Index: src/js/_enqueues/admin/common.js
===================================================================
--- src/js/_enqueues/admin/common.js	(revision 55306)
+++ src/js/_enqueues/admin/common.js	(working copy)
@@ -1702,6 +1702,26 @@
 				}
 			} );
 
+			// Close sidebar when focus moves outside of toggle and sidebar.
+			$( '#wp-admin-bar-menu-toggle, #adminmenumain' ).on( 'focusout', function( e ) {
+				var focusIsInToggle, focusIsInSidebar;
+
+				if ( ! $wpwrap.hasClass( 'wp-responsive-open' ) || ! document.hasFocus() ) {
+					return;
+				}
+				// A brief delay is required to allow focus to switch to another element.
+				setTimeout( function() {
+					focusIsInToggle  = $.contains( $( '#wp-admin-bar-menu-toggle' )[0], $( ':focus' )[0] );
+					focusIsInSidebar = $.contains( $( '#adminmenumain' )[0], $( ':focus' )[0] );
+
+					if ( ! focusIsInToggle && ! focusIsInSidebar ) {
+						console.log( { focusIsInToggle, focusIsInSidebar } );
+						$( '#wp-admin-bar-menu-toggle' ).trigger( 'click.wp-responsive' );
+					}
+				}, 10 );
+			} );
+
+
 			// Add menu events.
 			$adminmenu.on( 'click.wp-responsive', 'li.wp-has-submenu > a', function( event ) {
 				if ( ! $adminmenu.data('wp-responsive') ) {
@@ -1709,6 +1729,7 @@
 				}
 
 				$( this ).parent( 'li' ).toggleClass( 'selected' );
+				$( this ).trigger( 'focus' );
 				event.preventDefault();
 			});