disconnect an orphaned chrome.runtime message/port listener

content/apply.js

@@ -361,6 +361,9 @@
     // so we need to detach event listeners
     [docRewriteObserver, docRootObserver].forEach(ob => ob && ob.takeRecords() && ob.disconnect());
     window.removeEventListener(chrome.runtime.id, orphanCheck, true);
+    try {
+      chrome.runtime.onMessage.removeListener(applyOnMessage);
+    } catch (e) {}
   }
 
   function initDocRewriteObserver() {

content/install-hook-usercss.js

@@ -103,6 +103,9 @@
       // In Chrome content script is orphaned on an extension update/reload
       // so we need to detach event listeners
       removeEventListener(eventName, orphanCheckRequest, true);
+      try {
+        chrome.runtime.onConnect.removeListener(onConnected);
+      } catch (e) {}
     };
     dispatchEvent(new Event(eventName));
     addEventListener(eventName, orphanCheckRequest, true);

content/install-hook-userstyles.js

@@ -13,18 +13,7 @@
     ['', 'Chrome', 'Opera'].forEach(browser =>
       document.addEventListener('stylish' + type + browser, onClick)));
 
-  chrome.runtime.onMessage.addListener((msg, sender, sendResponse) => {
-    switch (msg.method) {
-      case 'ping':
-        // orphaned content script check
-        sendResponse(true);
-        break;
-      case 'openSettings':
-        openSettings();
-        sendResponse(true);
-        break;
-    }
-  });
+  chrome.runtime.onMessage.addListener(onMessage);
 
   new MutationObserver((mutations, observer) => {
     if (document.body) {
@@ -38,6 +27,19 @@
     }
   }).observe(document.documentElement, {childList: true});
 
+  function onMessage(msg, sender, sendResponse) {
+    switch (msg.method) {
+      case 'ping':
+        // orphaned content script check
+        sendResponse(true);
+        break;
+      case 'openSettings':
+        openSettings();
+        sendResponse(true);
+        break;
+    }
+  }
+
   /* since we are using "stylish-code-chrome" meta key on all browsers and
     US.o does not provide "advanced settings" on this url if browser is not Chrome,
     we need to fix this URL using "stylish-update-url" meta key
@@ -304,6 +306,9 @@
     ['Update', 'Install'].forEach(type =>
       ['', 'Chrome', 'Opera'].forEach(browser =>
         document.addEventListener('stylish' + type + browser, onClick)));
+    try {
+      chrome.runtime.onMessage.addListener(onMessage);
+    } catch (e) {}
   }
 })();