--- a/testing/marionette/action.js
+++ b/testing/marionette/action.js
@@ -12,17 +12,16 @@ Cu.import("chrome://marionette/content/a
 const {element} = Cu.import("chrome://marionette/content/element.js", {});
 const {
   InvalidArgumentError,
   MoveTargetOutOfBoundsError,
   UnsupportedOperationError,
 } = Cu.import("chrome://marionette/content/error.js", {});
 Cu.import("chrome://marionette/content/event.js");
 const {pprint} = Cu.import("chrome://marionette/content/format.js", {});
-Cu.import("chrome://marionette/content/interaction.js");
 
 this.EXPORTED_SYMBOLS = ["action"];
 
 // TODO? With ES 2016 and Symbol you can make a safer approximation
 // to an enum e.g. https://gist.github.com/xmlking/e86e4f15ec32b12c4689
 /**
  * Implements WebDriver Actions API: a low-level interface for providing
  * virtualised device input to the web browser.
@@ -1007,18 +1006,17 @@ action.dispatch = function(chain, window
  *     Current window global.
  *
  * @return {Promise}
  *     Promise for dispatching all tick-actions and pending DOM events.
  */
 action.dispatchTickActions = function(
     tickActions, tickDuration, window) {
   let pendingEvents = tickActions.map(toEvents(tickDuration, window));
-  return Promise.all(pendingEvents).then(
-      () => interaction.flushEventLoop(window));
+  return Promise.all(pendingEvents);
 };
 
 /**
  * Compute tick duration in milliseconds for a collection of actions.
  *
  * @param {Array.<action.Action>} tickActions
  *     List of actions for one tick.
  *

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_click.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_click.py
@@ -313,16 +313,51 @@ class TestClick(TestLegacyClick):
         button = self.marionette.find_element(By.TAG_NAME, "button")
         self.assertEqual("none", button.value_of_css_property("pointer-events"))
 
         with self.assertRaisesRegexp(errors.ElementClickInterceptedException,
                                      "does not have pointer events enabled"):
             button.click()
         self.assertFalse(self.marionette.execute_script("return window.clicked", sandbox=None))
 
+    def test_preventDefault(self):
+        self.marionette.navigate(inline("""
+            <button>click me</button>
+            <script>
+              let button = document.querySelector("button");
+              button.addEventListener("click", event => event.preventDefault());
+            </script>
+        """))
+        button = self.marionette.find_element(By.TAG_NAME, "button")
+        # should not time out
+        button.click()
+
+    def test_stopPropagation(self):
+        self.marionette.navigate(inline("""
+            <button>click me</button>
+            <script>
+              let button = document.querySelector("button");
+              button.addEventListener("click", event => event.stopPropagation());
+            </script>
+        """))
+        button = self.marionette.find_element(By.TAG_NAME, "button")
+        # should not time out
+        button.click()
+
+    def test_stopImmediatePropagation(self):
+        self.marionette.navigate(inline("""
+            <button>click me</button>
+            <script>
+              let button = document.querySelector("button");
+              button.addEventListener("click", event => event.stopImmediatePropagation());
+            </script>
+        """))
+        button = self.marionette.find_element(By.TAG_NAME, "button")
+        # should not time out
+        button.click()
 
 
 class TestClickNavigation(MarionetteTestCase):
 
     def setUp(self):
         super(TestClickNavigation, self).setUp()
 
         self.test_page = self.marionette.absolute_url("clicks.html")

--- a/testing/marionette/interaction.js
+++ b/testing/marionette/interaction.js
@@ -172,22 +172,22 @@ async function webdriverClickElement(el,
   a11y.assertVisible(acc, el, true);
   a11y.assertEnabled(acc, el, true);
   a11y.assertActionable(acc, el);
 
   // step 8
   if (el.localName == "option") {
     interaction.selectOption(el);
   } else {
+    // step 9
+    let clicked = interaction.flushEventLoop(containerEl);
     event.synthesizeMouseAtPoint(clickPoint.x, clickPoint.y, {}, win);
+    await clicked;
   }
 
-  // step 9
-  await interaction.flushEventLoop(win);
-
   // step 10
   // if the click causes navigation, the post-navigation checks are
   // handled by the load listener in listener.js
 }
 
 async function chromeClick(el, a11y) {
   if (!atom.isElementEnabled(el)) {
     throw new InvalidElementStateError("Element is not enabled");
@@ -282,46 +282,47 @@ interaction.selectOption = function(el) 
   }
 
   event.change(containerEl);
   event.mouseup(containerEl);
   event.click(containerEl);
 };
 
 /**
- * Flushes the event loop by requesting an animation frame.
- *
- * This will wait for the browser to repaint before returning, typically
- * flushing any queued events.
+ * Waits until the event loop has spun enough times to process the
+ * DOM events generated by clicking an element, or until the document
+ * is unloaded.
  *
- * If the document is unloaded during this request, the promise is
- * rejected.
- *
- * @param {Window} win
- *     Associated window.
+ * @param {Element} el
+ *     Element that is expected to receive the click.
  *
  * @return {Promise}
- *     Promise is accepted once event queue is flushed, or rejected if
- *     <var>win</var> has closed or been unloaded before the queue can
- *     be flushed.
+ *     Promise is resolved once <var>el</var> has been clicked
+ *     (its <code>click</code> event fires) or the document is unloaded.
  */
-interaction.flushEventLoop = async function(win) {
+interaction.flushEventLoop = async function(el) {
+  const win = el.ownerGlobal;
+  let unloadEv, clickEv;
+
   return new Promise(resolve => {
-    let handleEvent = () => {
-      win.removeEventListener("beforeunload", this);
-      resolve();
+    unloadEv = resolve;
+    clickEv = () => {
+      if (win.closed) {
+        resolve();
+      } else {
+        win.setTimeout(resolve, 0);
+      }
     };
 
-    if (win.closed) {
-      resolve();
-      return;
-    }
-
-    win.addEventListener("beforeunload", handleEvent);
-    win.requestAnimationFrame(handleEvent);
+    win.addEventListener("unload", unloadEv, {mozSystemGroup: true});
+    el.addEventListener("click", clickEv, {mozSystemGroup: true});
+  }).then(() => {
+    // only one event fires
+    win.removeEventListener("unload", unloadEv);
+    el.removeEventListener("click", clickEv);
   });
 };
 
 /**
  * Appends <var>path</var> to an <tt>&lt;input type=file&gt;</tt>'s
  * file list.
  *
  * @param {HTMLInputElement} el