Ticket #46540: 46540.diff

src/js/_enqueues/wp/customize/selective-refresh.js

@@ -660 +660 @@
                         nonce: api.settings.nonce.preview,
                         customize_theme: api.settings.theme.stylesheet,
                         customized: JSON.stringify( dirtyCustomized ),
-                        customize_changeset_uuid: api.settings.changeset.uuid
+                        customize_changeset_uuid: api.settings.changeset.uuid,
+                        customize_messenger_channel: api.settings.channel,
                 };
         };