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