Index: src/wp-admin/js/customize-widgets.js
===================================================================
--- src/wp-admin/js/customize-widgets.js	(revision 42833)
+++ src/wp-admin/js/customize-widgets.js	(working copy)
@@ -1630,7 +1630,7 @@
 				 */
 				getActiveSectionCount = function() {
 					return _.filter( panel.sections(), function( section ) {
-						return section.active();
+						return 'sidebar' === section.params.type && section.active();
 					} ).length;
 				};