diff --git a/background/background.js b/background/background.js
index 6d15e8d4..94da67a7 100644
--- a/background/background.js
+++ b/background/background.js
@@ -147,11 +147,18 @@ prefs.initializing.then(() => {
   refreshAllIcons();
 });
 
-navigatorUtil.onUrlChange(({tabId, frameId}, type) => {
+navigatorUtil.onUrlChange(({tabId, frameId, transitionQualifiers}, type) => {
   if (type === 'committed' && !frameId) {
-    // it seems that the tab icon would be reset when pressing F5. We
-    // invalidate the cache here so it would be refreshed.
+    // it seems that the tab icon would be reset by navigation. We
+    // invalidate the cache here so it would be refreshed by `apply.js`.
     tabIcons.delete(tabId);
+
+    // however, if the tab was swapped in by forward/backward buttons,
+    // `apply.js` doesn't notify the background to update the icon,
+    // so we have to refresh it manually.
+    if (transitionQualifiers.includes('forward_back')) {
+      msg.sendTab(tabId, {method: 'updateCount'}).catch(msg.broadcastError);
+    }
   }
 });
 
diff --git a/background/navigator-util.js b/background/navigator-util.js
index fb91d65c..ab08dffa 100644
--- a/background/navigator-util.js
+++ b/background/navigator-util.js
@@ -23,16 +23,19 @@ const navigatorUtil = (() => {
     chrome.webNavigation.onCommitted.addListener(data =>
       fixNTPUrl(data)
         .then(() => executeCallbacks(handler.urlChange, data, 'committed'))
+        .catch(console.error)
     );
 
     chrome.webNavigation.onHistoryStateUpdated.addListener(data =>
       fixNTPUrl(data)
         .then(() => executeCallbacks(handler.urlChange, data, 'historyStateUpdated'))
+        .catch(console.error)
     );
 
     chrome.webNavigation.onReferenceFragmentUpdated.addListener(data =>
       fixNTPUrl(data)
         .then(() => executeCallbacks(handler.urlChange, data, 'referenceFragmentUpdated'))
+        .catch(console.error)
     );
   }
 
diff --git a/content/apply.js b/content/apply.js
index 51df8ab7..e8d780b0 100644
--- a/content/apply.js
+++ b/content/apply.js
@@ -219,6 +219,10 @@ const APPLY = (() => {
           }
         });
         break;
+
+      case 'updateCount':
+        updateCount();
+        break;
     }
   }
 
@@ -336,11 +340,6 @@ const APPLY = (() => {
     }
     docRootObserver.firstStart();
 
-    // FIXME
-    // if (FF_BUG461 && (gotNewStyles || styles.needTransitionPatch)) {
-      // setContentsInPageContext();
-    // }
-
     if (!isOwnPage && !docRewriteObserver && styleElements.size) {
       initDocRewriteObserver();
     }