From 88c2d8ba25826048c2997dc49becfb2fdb4b6e0f Mon Sep 17 00:00:00 2001
From: Weston Ruter <westonruter@git.wordpress.org>
Date: Thu, 12 Oct 2017 05:16:40 +0000
Subject: [PATCH] Customize: Prevent showing confirmation dialog when leaving
 Customizer after previewing theme switch without making any changes.

Fixes #42173.


git-svn-id: https://develop.svn.wordpress.org/trunk@41845 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-admin/js/customize-controls.js | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/wp-admin/js/customize-controls.js b/src/wp-admin/js/customize-controls.js
index d13c9d17c6..7f0214b397 100644
--- a/src/wp-admin/js/customize-controls.js
+++ b/src/wp-admin/js/customize-controls.js
@@ -8384,6 +8384,15 @@
 			var isInsideIframe = false;
 
 			function isCleanState() {
+
+				/*
+				 * Handle special case of previewing theme switch since some settings (for nav menus and widgets)
+				 * are pre-dirty and non-active themes can only ever be auto-drafts.
+				 */
+				if ( ! api.state( 'activated' ).get() ) {
+					return 0 === api._latestRevision;
+				}
+
 				return api.state( 'saved' ).get() && 'auto-draft' !== api.state( 'changesetStatus' ).get();
 			}