diff --git a/js/dom.js b/js/dom.js
index c956d729..7ffb9ce6 100644
--- a/js/dom.js
+++ b/js/dom.js
@@ -392,3 +392,55 @@ function moveFocus(rootElement, step) {
     }
   }
 }
+
+// Accepts an array of pref names (values are fetched via prefs.get)
+// and establishes a two-way connection between the document elements and the actual prefs
+function setupLivePrefs(
+  IDs = Object.getOwnPropertyNames(prefs.defaults)
+    .filter(id => $('#' + id))
+) {
+  for (const id of IDs) {
+    const element = $('#' + id);
+    updateElement({id, element, force: true});
+    element.addEventListener('change', onChange);
+  }
+  prefs.subscribe(IDs, (id, value) => updateElement({id, value}));
+
+  function onChange() {
+    const value = getInputValue(this);
+    if (prefs.get(this.id) !== value) {
+      prefs.set(this.id, value);
+    }
+  }
+  function updateElement({
+    id,
+    value = prefs.get(id),
+    element = $('#' + id),
+    force,
+  }) {
+    if (!element) {
+      prefs.unsubscribe(IDs, updateElement);
+      return;
+    }
+    setInputValue(element, value, force);
+  }
+  function getInputValue(input) {
+    if (input.type === 'checkbox') {
+      return input.checked;
+    }
+    if (input.type === 'number') {
+      return Number(input.value);
+    }
+    return input.value;
+  }
+  function setInputValue(input, value, force = false) {
+    if (force || getInputValue(input) !== value) {
+      if (input.type === 'checkbox') {
+        input.checked = value;
+      } else {
+        input.value = value;
+      }
+      input.dispatchEvent(new Event('change', {bubbles: true, cancelable: true}));
+    }
+  }
+}
diff --git a/js/prefs.js b/js/prefs.js
index 5703e370..262eabf8 100644
--- a/js/prefs.js
+++ b/js/prefs.js
@@ -113,6 +113,8 @@ var prefs = (() => {
     initializing.then(() => setAll(changes.settings.newValue, true));
   });
 
+  let timer;
+
   // coalesce multiple pref changes in broadcast
   // let changes = {};
 
@@ -217,11 +219,10 @@ var prefs = (() => {
     }
     values[key] = value;
     emitChange(key, value);
-    if (synced) {
+    if (synced || timer) {
       return;
     }
-    // changes[key] = value;
-    debounce(syncPrefs);
+    timer = setTimeout(syncPrefs);
   }
 
   function emitChange(key, value) {
@@ -241,6 +242,7 @@ var prefs = (() => {
   function syncPrefs() {
     // FIXME: we always set the entire object? Ideally, this should only use `changes`.
     chrome.storage.sync.set({settings: values});
+    timer = null;
   }
 
   function equal(a, b) {
@@ -263,7 +265,7 @@ var prefs = (() => {
   }
 
   function contextDeleteMissing() {
-    return CHROME && (
+    return /Chrome\/\d+/.test(navigator.userAgent) && (
       // detect browsers without Delete by looking at the end of UA string
       /Vivaldi\/[\d.]+$/.test(navigator.userAgent) ||
       // Chrome and co.
@@ -272,57 +274,17 @@ var prefs = (() => {
       !Array.from(navigator.plugins).some(p => p.name === 'Shockwave Flash')
     );
   }
+
+  function deepCopy(obj) {
+    if (!obj || typeof obj !== 'object') {
+      return obj;
+    }
+    if (Array.isArray(obj)) {
+      return obj.map(deepCopy);
+    }
+    return Object.keys(obj).reduce((output, key) => {
+      output[key] = deepCopy(obj[key]);
+      return output;
+    }, {});
+  }
 })();
-
-
-// Accepts an array of pref names (values are fetched via prefs.get)
-// and establishes a two-way connection between the document elements and the actual prefs
-function setupLivePrefs(
-  IDs = Object.getOwnPropertyNames(prefs.defaults)
-    .filter(id => $('#' + id))
-) {
-  for (const id of IDs) {
-    const element = $('#' + id);
-    updateElement({id, element, force: true});
-    element.addEventListener('change', onChange);
-  }
-  prefs.subscribe(IDs, (id, value) => updateElement({id, value}));
-
-  function onChange() {
-    const value = getInputValue(this);
-    if (prefs.get(this.id) !== value) {
-      prefs.set(this.id, value);
-    }
-  }
-  function updateElement({
-    id,
-    value = prefs.get(id),
-    element = $('#' + id),
-    force,
-  }) {
-    if (!element) {
-      prefs.unsubscribe(IDs, updateElement);
-      return;
-    }
-    setInputValue(element, value, force);
-  }
-  function getInputValue(input) {
-    if (input.type === 'checkbox') {
-      return input.checked;
-    }
-    if (input.type === 'number') {
-      return Number(input.value);
-    }
-    return input.value;
-  }
-  function setInputValue(input, value, force = false) {
-    if (force || getInputValue(input) !== value) {
-      if (input.type === 'checkbox') {
-        input.checked = value;
-      } else {
-        input.value = value;
-      }
-      input.dispatchEvent(new Event('change', {bubbles: true, cancelable: true}));
-    }
-  }
-}