From af640568fe3783ff4af2647306093d1e4acd0615 Mon Sep 17 00:00:00 2001
From: Weston Ruter <westonruter@git.wordpress.org>
Date: Thu, 10 Nov 2016 22:42:38 +0000
Subject: [PATCH] Customize: Prevent previewer from appearing to freeze when
 refreshing too fast.

Fixes race condition issue where a previous iframe fails to get destroyed, leaving a iframe pending loading persistently shown.

Props nikeo, westonruter.
Fixes #38728.


git-svn-id: https://develop.svn.wordpress.org/trunk@39199 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-admin/js/customize-controls.js | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/wp-admin/js/customize-controls.js b/src/wp-admin/js/customize-controls.js
index 25145a1ae6..17159a0964 100644
--- a/src/wp-admin/js/customize-controls.js
+++ b/src/wp-admin/js/customize-controls.js
@@ -3930,18 +3930,18 @@
 			} );
 
 			previewer.loading.done( function( readyData ) {
-				var loadingFrame = this, previousPreview, onceSynced;
+				var loadingFrame = this, onceSynced;
 
-				previousPreview = previewer.preview;
 				previewer.preview = loadingFrame;
 				previewer.targetWindow( loadingFrame.targetWindow() );
 				previewer.channel( loadingFrame.channel() );
 
 				onceSynced = function() {
 					loadingFrame.unbind( 'synced', onceSynced );
-					if ( previousPreview ) {
-						previousPreview.destroy();
+					if ( previewer._previousPreview ) {
+						previewer._previousPreview.destroy();
 					}
+					previewer._previousPreview = previewer.preview;
 					previewer.deferred.active.resolve();
 					delete previewer.loading;
 				};