firefox used to display "loading..." on back sometimes

app/assets/javascripts/discourse/views/topic_view.js

@@ -111,6 +111,9 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
 
     this.set('screenTrack', null);
     this.resetExamineDockCache();
+
+    // this happens after route exit, stuff could have trickled in
+    this.set('controller.controllers.header.showExtraInfo', false)
   },
 
   didInsertElement: function(e) {