diff --git a/js/dom.js b/js/dom.js
index b95627d5..a3db3148 100644
--- a/js/dom.js
+++ b/js/dom.js
@@ -134,27 +134,31 @@ function scrollElementIntoView(element, {invalidMarginRatio = 0} = {}) {
 }
 
 
-function animateElement(
-  element, {
-    className = 'highlight',
-    removeExtraClasses = [],
-    onComplete,
-  } = {}) {
-  return element && new Promise(resolve => {
-    element.addEventListener('animationend', () => {
-      element.classList.remove(
-        className,
-        // In Firefox, `resolve()` might be called one frame later.
-        // This is helpful to clean-up on the same frame
-        ...removeExtraClasses
-      );
-      // TODO: investigate why animation restarts for 'display' modification in .then()
-      if (typeof onComplete === 'function') {
-        onComplete.call(element);
-      }
+/**
+ * @param {HTMLElement} el
+ * @param {string} [cls] - class name that defines or starts an animation
+ * @param [removeExtraClasses] - class names to remove at animation end in the *same* paint frame,
+ *        which is needed in e.g. Firefox as it may call resolve() in the next frame
+ * @returns {Promise<void>}
+ */
+function animateElement(el, cls = 'highlight', ...removeExtraClasses) {
+  return !el ? Promise.resolve(el) : new Promise(resolve => {
+    let onDone = () => {
+      el.classList.remove(cls, ...removeExtraClasses);
+      onDone = null;
       resolve();
-    }, {once: true});
-    element.classList.add(className);
+    };
+    requestAnimationFrame(() => {
+      if (onDone) {
+        const style = getComputedStyle(el);
+        if (style.animationName === 'none' || !parseFloat(style.animationDuration)) {
+          el.removeEventListener('animationend', onDone);
+          onDone();
+        }
+      }
+    });
+    el.addEventListener('animationend', onDone, {once: true});
+    el.classList.add(cls);
   });
 }
 
diff --git a/manage/config-dialog.js b/manage/config-dialog.js
index 9bb3bbd6..756a12ce 100644
--- a/manage/config-dialog.js
+++ b/manage/config-dialog.js
@@ -70,7 +70,6 @@ function configDialog(style) {
 
     if (isPopup) {
       adjustSizeForPopup(box);
-      box.style.animationDuration = '0s';
     }
 
     box.addEventListener('change', onchange);
diff --git a/manage/import-export.js b/manage/import-export.js
index 15261baf..5c19b140 100644
--- a/manage/import-export.js
+++ b/manage/import-export.js
@@ -21,10 +21,9 @@ onDOMready().then(() => {
         this.classList.remove('fadeout');
       }
     },
-    ondragend() {
-      animateElement(this, {className: 'fadeout', removeExtraClasses: ['dropzone']}).then(() => {
-        this.style.animationDuration = '';
-      });
+    async ondragend() {
+      await animateElement(this, 'fadeout', 'dropzone');
+      this.style.animationDuration = '';
     },
     ondragleave(event) {
       try {
diff --git a/manage/incremental-search.js b/manage/incremental-search.js
index 99416784..791cdd2c 100644
--- a/manage/incremental-search.js
+++ b/manage/incremental-search.js
@@ -69,7 +69,7 @@ onDOMready().then(() => {
       focusedLink = $('.style-name-link', found);
       focusedName = found.styleNameLowerCase;
       scrollElementIntoView(found, {invalidMarginRatio: .25});
-      animateElement(found, {className: 'highlight-quick'});
+      animateElement(found, 'highlight-quick');
       replaceInlineStyle({
         width: focusedLink.offsetWidth + 'px',
         height: focusedLink.offsetHeight + 'px',
diff --git a/manage/manage.js b/manage/manage.js
index 888da2e8..972c659b 100644
--- a/manage/manage.js
+++ b/manage/manage.js
@@ -728,15 +728,13 @@ function embedOptions() {
   options.focus();
 }
 
-function unembedOptions() {
+async function unembedOptions() {
   const options = $('#stylus-embedded-options');
   if (options) {
     options.contentWindow.document.body.classList.add('scaleout');
     options.classList.add('fadeout');
-    animateElement(options, {
-      className: 'fadeout',
-      onComplete: () => options.remove(),
-    });
+    await animateElement(options, 'fadeout');
+    options.remove();
   }
 }
 
diff --git a/msgbox/msgbox.css b/msgbox/msgbox.css
index 4f349613..1f5058f0 100644
--- a/msgbox/msgbox.css
+++ b/msgbox/msgbox.css
@@ -12,6 +12,10 @@
   -moz-user-select: none;
 }
 
+#stylus-popup #message-box {
+  animation: none;
+}
+
 #message-box > div {
   top: 3rem;
   right: 3rem;
diff --git a/msgbox/msgbox.js b/msgbox/msgbox.js
index 6a409f9f..3daff5d5 100644
--- a/msgbox/msgbox.js
+++ b/msgbox/msgbox.js
@@ -94,10 +94,8 @@ function messageBox({
   function resolveWith(value) {
     unbindGlobalListeners();
     setTimeout(messageBox.resolve, 0, value);
-    animateElement(messageBox.element, {
-      className: 'fadeout',
-      onComplete: removeSelf,
-    });
+    animateElement(messageBox.element, 'fadeout')
+      .then(removeSelf);
     if (messageBox.element.contains(document.activeElement)) {
       messageBox.originalFocus.focus();
     }
diff --git a/popup/popup.js b/popup/popup.js
index 979fdd4c..bc9df1b2 100644
--- a/popup/popup.js
+++ b/popup/popup.js
@@ -495,10 +495,8 @@ Object.assign(handleEvent, {
     const menuActive = $('.menu[data-display=true]');
     if (menuActive) {
       // fade-out style menu
-      animateElement(menu, {
-        className: 'lights-on',
-        onComplete: () => (menu.dataset.display = false),
-      });
+      animateElement(menu, 'lights-on')
+        .then(() => (menu.dataset.display = false));
       window.onkeydown = null;
     } else {
       $('.menu-title', entry).textContent = $('.style-name', entry).textContent;
@@ -567,10 +565,8 @@ Object.assign(handleEvent, {
     function confirm(ok) {
       if (ok) {
         // fade-out deletion confirmation dialog
-        animateElement(box, {
-          className: 'lights-on',
-          onComplete: () => (box.dataset.display = false),
-        });
+        animateElement(box, 'lights-on')
+          .then(() => (box.dataset.display = false));
         window.onkeydown = null;
         API.deleteStyle(id);
       } else {