diff --git a/background/background.js b/background/background.js
index 50843039..cdbfd33e 100644
--- a/background/background.js
+++ b/background/background.js
@@ -13,6 +13,7 @@ window.API_METHODS = Object.assign(window.API_METHODS || {}, {
   // getStyles,
   getSectionsByUrl: styleManager.getSectionsByUrl,
   getSectionsById: styleManager.getSectionsById,
+  getStylesInfo: styleManager.getStylesInfo,
   // saveStyle,
   // deleteStyle,
 
diff --git a/background/style-manager.js b/background/style-manager.js
index d662b217..f89696fe 100644
--- a/background/style-manager.js
+++ b/background/style-manager.js
@@ -1,4 +1,4 @@
-/* global createCache db calcStyleDigest normalizeStyleSections db */
+/* global createCache db calcStyleDigest normalizeStyleSections db promisify */
 'use strict';
 
 const styleManager = (() => {
@@ -8,18 +8,37 @@ const styleManager = (() => {
   const compiledRe = createCache();
   const compiledExclusion = createCache();
   const BAD_MATCHER = {test: () => false};
+  const tabQuery = promisify(chrome.tabs.query.bind(chrome.tabs));
+  const tabSendMessage = promisify(chrome.tabs.sendMessage.bind(chrome.tabs));
+  const runtimeSendMessage = promisify(chrome.runtime.sendMessage.bind(chrome.runtime));
 
   // FIXME: do we have to prepare `styles` map for all methods?
   return ensurePrepared({
-    getSectionsForURL,
+    styles,
+    cachedStyleForUrl,
+    getStylesInfo,
+    getSectionsByUrl,
     installStyle,
     deleteStyle,
     setStyleExclusions,
-    editSave
+    editSave,
+    toggleStyle
     // TODO: get all styles API?
     // TODO: get style by ID?
   });
 
+  function toggleStyle(id, enabled) {
+    const style = styles.get(id);
+    style.enabled = enabled;
+    return saveStyle(style)
+      .then(() => broadcastMessage('styleUpdated', {id, enabled}));
+  }
+
+  function getStylesInfo() {
+    // FIXME: remove code?
+    return [...styles.values()];
+  }
+
   function editSave() {}
 
   function setStyleExclusions() {}
@@ -105,14 +124,14 @@ const styleManager = (() => {
     }
   }
 
-  function getSectionsForURL(url) {
+  function getSectionsByUrl(url) {
     // if (!URLS.supported(url) || prefs.get('disableAll')) {
       // return [];
     // }
     let result = cachedStyleForUrl.get(url);
     if (!result) {
       result = [];
-      for (const style of styles) {
+      for (const style of styles.values()) {
         if (!urlMatchStyle(url, style)) {
           continue;
         }
@@ -213,4 +232,81 @@ const styleManager = (() => {
   function getUrlNoHash(url) {
     return url.split('#')[0];
   }
+
+  function cleanData(method, data) {
+    if (
+      (method === 'styleUpdated' || method === 'styleAdded') &&
+      (data.sections || data.sourceCode)
+    ) {
+      // apply/popup/manage use only meta for these two methods,
+      // editor may need the full code but can fetch it directly,
+      // so we send just the meta to avoid spamming lots of tabs with huge styles
+      return getStyleWithNoCode(data);
+    }
+    return output;
+  }
+
+  function isExtensionStyle(id) {
+    // TODO
+    // const style = styles.get(id);
+    // if (!style)
+    return false;
+  }
+
+  function broadcastMessage(method, data) {
+    const pendingPrivilage = runtimeSendMessage({method, cleanData(method, data)});
+    // const affectsAll = !msg.affects || msg.affects.all;
+    // const affectsOwnOriginOnly =
+    // !affectsAll && (msg.affects.editor || msg.affects.manager);
+    // const affectsTabs = affectsAll || affectsOwnOriginOnly;
+    // const affectsIcon = affectsAll || msg.affects.icon;
+    // const affectsPopup = affectsAll || msg.affects.popup;
+    // const affectsSelf = affectsPopup || msg.prefs;
+    // notify all open extension pages and popups
+    // if (affectsSelf) {
+      // msg.tabId = undefined;
+      // sendMessage(msg, ignoreChromeError);
+    // }
+    // notify tabs
+    if (affectsTabs || affectsIcon) {
+      const notifyTab = tab => {
+        if (!styleUpdated
+        && (affectsTabs || URLS.optionsUI.includes(tab.url))
+        // own pages are already notified via sendMessage
+        && !(affectsSelf && tab.url.startsWith(URLS.ownOrigin))
+        // skip lazy-loaded aka unloaded tabs that seem to start loading on message in FF
+        && (!FIREFOX || tab.width)) {
+          msg.tabId = tab.id;
+          sendMessage(msg, ignoreChromeError);
+        }
+        if (affectsIcon) {
+          // eslint-disable-next-line no-use-before-define
+          // debounce(API.updateIcon, 0, {tab});
+        }
+      };
+      // list all tabs including chrome-extension:// which can be ours
+      Promise.all([
+        queryTabs(isExtensionStyle(data.id) ? {url: URLS.ownOrigin + '*'} : {}),
+        getActiveTab(),
+      ]).then(([tabs, activeTab]) => {
+        const activeTabId = activeTab && activeTab.id;
+        for (const tab of tabs) {
+          invokeOrPostpone(tab.id === activeTabId, notifyTab, tab);
+        }
+      });
+    }
+    // notify self: the message no longer is sent to the origin in new Chrome
+    if (typeof onRuntimeMessage !== 'undefined') {
+      onRuntimeMessage(originalMessage);
+    }
+    // notify apply.js on own pages
+    if (typeof applyOnMessage !== 'undefined') {
+      applyOnMessage(originalMessage);
+    }
+    // propagate saved style state/code efficiently
+    if (styleUpdated) {
+      msg.refreshOwnTabs = false;
+      API.refreshAllTabs(msg);
+    }
+  }
 })();
diff --git a/content/api.js b/content/api.js
index 6409072f..3fe85d68 100644
--- a/content/api.js
+++ b/content/api.js
@@ -1,3 +1,4 @@
+/* global promisify */
 'use strict';
 
 const API = (() => {
@@ -12,29 +13,13 @@ const API = (() => {
   function sendMessage(msg) {
     return runtimeSendMessage(msg)
       .then(result => {
-        if (result.__ERROR__) {
+        if (result && result.__ERROR__) {
           throw new Error(result.__ERROR__);
         }
         return result;
       });
   }
 
-  function promisify(fn) {
-    return (...args) =>
-      new Promise((resolve, reject) => {
-        fn(...args, (...result) => {
-          if (chrome.runtime.lastError) {
-            reject(chrome.runtime.lastError);
-            return;
-          }
-          resolve(
-            result.length === 0 ? undefined :
-            result.length === 1 ? result[1] : result
-          );
-        });
-      });
-  }
-
   function invokeBG(name, args) {
     return preparing.then(BG => {
       if (!BG) {
@@ -48,7 +33,11 @@ const API = (() => {
       if (BG !== window) {
         args = BG.deepCopy(args);
       }
-      return BG.API_METHODS[name](...args)
+      const fn = BG.API_METHODS[name];
+      if (!fn) {
+        throw new Error(`unknown API method: ${name}`);
+      }
+      return Promise.resolve(fn(...args))
         .then(BG.deepCopy);
     });
   }
diff --git a/content/apply.js b/content/apply.js
index 968d0d0a..8c07f685 100644
--- a/content/apply.js
+++ b/content/apply.js
@@ -116,7 +116,7 @@
         break;
 
       case 'styleUpdated':
-        if (request.codeIsUpdated === false) {
+        if (!request.codeIsUpdated) {
           applyStyleState(request.style);
           break;
         }
diff --git a/js/messaging.js b/js/messaging.js
index ccca8de6..1f594fab 100644
--- a/js/messaging.js
+++ b/js/messaging.js
@@ -104,71 +104,6 @@ if (FIREFOX_NO_DOM_STORAGE) {
   Object.defineProperty(window, 'sessionStorage', {value: {}});
 }
 
-function notifyAllTabs(msg) {
-  const originalMessage = msg;
-  const styleUpdated = msg.method === 'styleUpdated' || msg.method === 'exclusionsUpdated';
-  if (styleUpdated || msg.method === 'styleAdded') {
-    // apply/popup/manage use only meta for these two methods,
-    // editor may need the full code but can fetch it directly,
-    // so we send just the meta to avoid spamming lots of tabs with huge styles
-    msg = Object.assign({}, msg, {
-      style: getStyleWithNoCode(msg.style)
-    });
-  }
-  const affectsAll = !msg.affects || msg.affects.all;
-  const affectsOwnOriginOnly = !affectsAll && (msg.affects.editor || msg.affects.manager);
-  const affectsTabs = affectsAll || affectsOwnOriginOnly;
-  const affectsIcon = affectsAll || msg.affects.icon;
-  const affectsPopup = affectsAll || msg.affects.popup;
-  const affectsSelf = affectsPopup || msg.prefs;
-  // notify all open extension pages and popups
-  if (affectsSelf) {
-    msg.tabId = undefined;
-    sendMessage(msg, ignoreChromeError);
-  }
-  // notify tabs
-  if (affectsTabs || affectsIcon) {
-    const notifyTab = tab => {
-      if (!styleUpdated
-      && (affectsTabs || URLS.optionsUI.includes(tab.url))
-      // own pages are already notified via sendMessage
-      && !(affectsSelf && tab.url.startsWith(URLS.ownOrigin))
-      // skip lazy-loaded aka unloaded tabs that seem to start loading on message in FF
-      && (!FIREFOX || tab.width)) {
-        msg.tabId = tab.id;
-        sendMessage(msg, ignoreChromeError);
-      }
-      if (affectsIcon) {
-        // eslint-disable-next-line no-use-before-define
-        debounce(API.updateIcon, 0, {tab});
-      }
-    };
-    // list all tabs including chrome-extension:// which can be ours
-    Promise.all([
-      queryTabs(affectsOwnOriginOnly ? {url: URLS.ownOrigin + '*'} : {}),
-      getActiveTab(),
-    ]).then(([tabs, activeTab]) => {
-      const activeTabId = activeTab && activeTab.id;
-      for (const tab of tabs) {
-        invokeOrPostpone(tab.id === activeTabId, notifyTab, tab);
-      }
-    });
-  }
-  // notify self: the message no longer is sent to the origin in new Chrome
-  if (typeof onRuntimeMessage !== 'undefined') {
-    onRuntimeMessage(originalMessage);
-  }
-  // notify apply.js on own pages
-  if (typeof applyOnMessage !== 'undefined') {
-    applyOnMessage(originalMessage);
-  }
-  // propagate saved style state/code efficiently
-  if (styleUpdated) {
-    msg.refreshOwnTabs = false;
-    API.refreshAllTabs(msg);
-  }
-}
-
 function sendMessage(msg, callback) {
   /*
   Promise mode [default]:
diff --git a/js/promisify.js b/js/promisify.js
new file mode 100644
index 00000000..4c1ae9e3
--- /dev/null
+++ b/js/promisify.js
@@ -0,0 +1,17 @@
+'use strict';
+
+function promisify(fn) {
+  return (...args) =>
+    new Promise((resolve, reject) => {
+      fn(...args, (...result) => {
+        if (chrome.runtime.lastError) {
+          reject(chrome.runtime.lastError);
+          return;
+        }
+        resolve(
+          result.length === 0 ? undefined :
+          result.length === 1 ? result[0] : result
+        );
+      });
+    });
+}
diff --git a/manage.html b/manage.html
index 20cd9618..85d5e3b7 100644
--- a/manage.html
+++ b/manage.html
@@ -153,9 +153,11 @@
     </p>
   </template>
 
+  <script src="js/promisify.js"></script>
   <script src="js/dom.js"></script>
   <script src="js/messaging.js"></script>
   <script src="js/prefs.js"></script>
+  <script src="content/api.js"></script>
   <script src="content/apply.js"></script>
   <script src="js/localization.js"></script>
   <script src="manage/filters.js"></script>
diff --git a/manage/manage.js b/manage/manage.js
index 275dcba8..0430c371 100644
--- a/manage/manage.js
+++ b/manage/manage.js
@@ -32,7 +32,7 @@ const OWN_ICON = chrome.runtime.getManifest().icons['16'];
 const handleEvent = {};
 
 Promise.all([
-  API.getStyles({omitCode: !BG}),
+  API.getStylesInfo(),
   urlFilterParam && API.searchDB({query: 'url:' + urlFilterParam}),
   onDOMready().then(initGlobalEvents),
 ]).then(args => {
@@ -195,7 +195,7 @@ function createStyleElement({style, name}) {
     };
   }
   const parts = createStyleElement.parts;
-  const configurable = style.usercssData && Object.keys(style.usercssData.vars).length > 0;
+  const configurable = style.usercssData && style.usercssData.vars && Object.keys(style.usercssData.vars).length > 0;
   parts.checker.checked = style.enabled;
   parts.nameLink.textContent = tWordBreak(style.name);
   parts.nameLink.href = parts.editLink.href = parts.editHrefBase + style.id;
@@ -403,10 +403,7 @@ Object.assign(handleEvent, {
   },
 
   toggle(event, entry) {
-    API.saveStyle({
-      id: entry.styleId,
-      enabled: this.matches('.enable') || this.checked,
-    });
+    API.toggleStyle(entry.styleId, this.matches('.enable') || this.checked);
   },
 
   check(event, entry) {
diff --git a/manifest.json b/manifest.json
index 86421bc8..ced9f3a0 100644
--- a/manifest.json
+++ b/manifest.json
@@ -23,6 +23,7 @@
   ],
   "background": {
     "scripts": [
+      "js/promisify.js",
       "js/messaging.js",
       "js/storage-util.js",
       "js/sections-equal.js",
@@ -60,7 +61,7 @@
       "run_at": "document_start",
       "all_frames": true,
       "match_about_blank": true,
-      "js": ["content/api.js", "content/apply.js"]
+      "js": ["js/promisify.js", "content/api.js", "content/apply.js"]
     },
     {
       "matches": ["http://userstyles.org/*", "https://userstyles.org/*"],