--- a/gfx/layers/apz/test/mochitest/test_bug1277814.html
+++ b/gfx/layers/apz/test/mochitest/test_bug1277814.html
@@ -12,25 +12,37 @@ https://bugzilla.mozilla.org/show_bug.cg
   <script type="application/javascript" src="apz_test_native_event_utils.js"></script>
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
   <script type="application/javascript">
     function* test(testDriver) {
       // Trigger the buggy scenario
       var subframe = document.getElementById('bug1277814-div');
       subframe.classList.add('a');
 
+      // The transform change is animated, so let's step through 1s of animation
+      var utils = SpecialPowers.getDOMWindowUtils(window);
+      for (var i = 0; i < 60; i++) {
+        utils.advanceTimeAndRefresh(16);
+      }
+      utils.restoreNormalRefresh();
+
+      // Wait for the layer tree with any updated dispatch-to-content region to
+      // get pushed over to the APZ
+      yield waitForAllPaints(function() {
+        flushApzRepaints(testDriver);
+      });
+
       // Trigger layerization of the subframe by scrolling the wheel over it
-      moveMouseAndScrollWheelOver(subframe, 10, 10, testDriver);
+      yield moveMouseAndScrollWheelOver(subframe, 10, 10, testDriver);
 
       // Give APZ the chance to compute a displayport, and content
       // to render based on it.
       yield waitForApzFlushedRepaints(testDriver);
 
       // Examine the content-side APZ test data
-      var utils = SpecialPowers.getDOMWindowUtils(window);
       var contentTestData = utils.getContentAPZTestData();
 
       // Test that the scroll frame for the div 'bug1277814-div' appears in
       // the APZ test data. The bug this test is for causes the displayport
       // calculation for this scroll frame to go wrong, causing it not to
       // become layerized.
       contentTestData = convertTestData(contentTestData);
       var foundIt = false;