diff --git a/resources/mmv/mmv.js b/resources/mmv/mmv.js
index 0736f832a..b7ea46dd7 100644
--- a/resources/mmv/mmv.js
+++ b/resources/mmv/mmv.js
@@ -44,6 +44,7 @@ const ThumbnailWidthCalculator = require( './mmv.ThumbnailWidthCalculator.js' );
 const { extensions, useThumbnailGuessing } = require( './config.json' );
 
 const router = require( 'mediawiki.router' );
+let comingFromHashChange = false;
 
 /**
  * Analyses the page, looks for image content and sets up the hooks
@@ -95,7 +96,7 @@ class MultimediaViewer {
 		 */
 		this.router = router;
 		this.setupRouter();
-		this.comingFromHashChange = false;
+		comingFromHashChange = false;
 
 		/**
 		 * UI object used to display the pictures in the page.
@@ -685,8 +686,8 @@ class MultimediaViewer {
 		this.viewLogger.recordViewDuration();
 		this.viewLogger.unattach();
 
-		if ( this.comingFromHashChange ) {
-			this.comingFromHashChange = false;
+		if ( comingFromHashChange ) {
+			comingFromHashChange = false;
 		} else {
 			this.router.back();
 		}
@@ -706,7 +707,7 @@ class MultimediaViewer {
 		// handle empty hashes, and anchor links (page sections, possibly including /)
 		this.router.addRoute( /.*$/, () => {
 			if ( this.isOpen ) {
-				this.comingFromHashChange = true;
+				comingFromHashChange = true;
 				document.title = this.createDocumentTitle( null );
 				if ( this.ui ) {
 					// FIXME triggers mmv-close event, which calls viewer.close()