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+++ b/layout/generic/test/test_bug784410.html
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+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Test bug 784410</title>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="application/javascript" src="/tests/SimpleTest/EventUtils.js"></script>
+  <script src="/tests/SimpleTest/paint_listener.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<p id="display"></p>
+<div id="outer" style="overflow:auto; height:200px; border:2px dotted black; transform: translateY(1px)" onscroll="doneScroll()">
+  <div id="d" style="overflow:auto; height:102px;" onscroll="doneScroll()">
+    <div id="inner" style="height:100.1px; border:1px solid black; background:yellow;">Hello</div>
+  </div>
+  <div style="height:500px;"></div>
+</div>
+<pre id="test">
+<script class="testbody" type="text/javascript;version=1.7">
+var sel = window.getSelection();
+var outer = document.getElementById("outer");
+var d = document.getElementById("d");
+var inner = document.getElementById("inner");
+var smoothScrollPref = "general.smoothScroll";
+
+function innerScrollOffset() {
+  return inner.getBoundingClientRect().top - d.getBoundingClientRect().top;
+}
+var innerStartScrollOffset = innerScrollOffset();
+
+var step = 0;
+function doneScroll() {
+  ++step;
+  switch (step) {
+  case 1:
+    is(innerScrollOffset(), innerStartScrollOffset, "Inner element should not have scrolled down");
+    ok(outer.scrollTop > 0, "Outer element should have scrolled down");
+
+    outer.scrollTop = 0;
+    break;
+  case 2:
+    // Wait for paints to flush, so APZ is notified of the new scroll offset.
+    sendWheelAndPaint(inner, 4, 4,
+      { deltaMode: WheelEvent.DOM_DELTA_LINE, deltaY: 1 },
+      function() {});
+    break;
+  case 3:
+    is(innerScrollOffset(), innerStartScrollOffset, "Inner element should not have scrolled down");
+    ok(outer.scrollTop > 0, "Outer element should have scrolled down");
+    
+    SpecialPowers.DOMWindowUtils.restoreNormalRefresh();
+    SimpleTest.finish();
+    break;
+  }
+}
+
+function test() {
+  sel.collapse(inner.firstChild, 2);
+  synthesizeKey("VK_PAGE_DOWN", {});
+}
+
+SimpleTest.waitForExplicitFinish();
+SimpleTest.waitForFocus(function() {
+  SpecialPowers.pushPrefEnv({"set":[[smoothScrollPref, false]]}, test);
+});
+</script>
+</pre>
+</body>
+</html>