Ticket #30690: 30690.diff

src/wp-admin/js/customize-widgets.js

@@ -641 +641 @@
                                                 selectSidebarItem( selfSidebarItem );
                                         }
                                 } );
+
+                                if ( 1 === $sidebarItems.length ) {
+                                        self.container.find( '.move-widget' ).hide();
+                                } else {
+                                        self.container.find( '.move-widget' ).show();
+                                }
                         };
 
                         updateAvailableSidebars();