Ticket #42162: 42162.0.diff

src/wp-includes/js/customize-preview.js

@@ -451 +451 @@
                         if ( ! api.settings.theme.active ) {
                                 queryParams.customize_theme = api.settings.theme.stylesheet;
                         }
+
+                        // Ensure preview nonce is included with every customized request, to allow post data to be read.
+                        queryParams.customize_preview_nonce = api.settings.nonce.preview;
+
                         urlParser.search = $.param( queryParams );
                         options.url = urlParser.href;
                 };