diff --git a/testing/mochitest/harness-overlay.xul b/testing/mochitest/harness-overlay.xul
index 33420b8e0d9..d2c7e20ec21 100644
--- a/testing/mochitest/harness-overlay.xul
+++ b/testing/mochitest/harness-overlay.xul
@@ -82,7 +82,7 @@ function loadTests()
         </div>
         <div class="clear"></div>
         <div class="frameholder">
-          <iframe type="content" scrolling="no" id="testframe" width="550" height="350" mozallowfullscreen="true"></iframe>
+          <iframe type="content" scrolling="no" id="testframe" width="550" height="350"></iframe>
         </div>
         <div class="clear"></div>
         <div class="toggle">
diff --git a/testing/mochitest/plain-loop.html b/testing/mochitest/plain-loop.html
index 6ea6ee0e133..787cb75d42f 100644
--- a/testing/mochitest/plain-loop.html
+++ b/testing/mochitest/plain-loop.html
@@ -43,7 +43,7 @@ function loadTests()
         </div>
         <div class="clear"></div>
         <div class="frameholder">
-          <iframe type="content" scrolling="no" id="testframe" width="550" height="350" mozallowfullscreen="true"></iframe>
+          <iframe type="content" scrolling="no" id="testframe" width="550" height="350"></iframe>
         </div>
         <div class="clear"></div>
         <div class="toggle">
diff --git a/testing/mochitest/server.js b/testing/mochitest/server.js
index b4933849cb8..cee4f32bca1 100644
--- a/testing/mochitest/server.js
+++ b/testing/mochitest/server.js
@@ -620,7 +620,7 @@ function testListing(metadata, response)
           ),
           DIV({class: "clear"}),
           DIV({class: "frameholder"},
-            IFRAME({scrolling: "no", id: "testframe", width: "500", height: "300", mozallowfullscreen: "true"})
+            IFRAME({scrolling: "no", id: "testframe", width: "500", height: "300"})
           ),
           DIV({class: "clear"}),
           DIV({class: "toggle"},
diff --git a/testing/mochitest/tests/Makefile.in b/testing/mochitest/tests/Makefile.in
index 6686fc7f741..67086806245 100644
--- a/testing/mochitest/tests/Makefile.in
+++ b/testing/mochitest/tests/Makefile.in
@@ -27,7 +27,6 @@ _TEST_FILES = \
   test_SpecialPowersExtension.html \
   test_SpecialPowersExtension2.html \
   file_SpecialPowersFrame1.html \
-  test_cancelFullScreen.html \
   $(NULL)
 
 ifneq ($(OS_TARGET),Android)
diff --git a/testing/mochitest/tests/SimpleTest/SimpleTest.js b/testing/mochitest/tests/SimpleTest/SimpleTest.js
index 776093e0142..1ac9509b981 100644
--- a/testing/mochitest/tests/SimpleTest/SimpleTest.js
+++ b/testing/mochitest/tests/SimpleTest/SimpleTest.js
@@ -680,10 +680,6 @@ SimpleTest.executeSoon = function(aFunc) {
  * SimpleTest.waitForExplicitFinish() has been invoked.
 **/
 SimpleTest.finish = function () {
-    // Cancel element fullscreen mode due to Bug 728893
-    if (document && document.mozFullScreenElement) {
-        document.mozCancelFullScreen();
-    }
     if (SimpleTest._expectingUncaughtException) {
         SimpleTest.ok(false, "expectUncaughtException was called but no uncaught exception was detected!");
     }
diff --git a/testing/mochitest/tests/test_cancelFullScreen.html b/testing/mochitest/tests/test_cancelFullScreen.html
deleted file mode 100644
index dcc8ae1eb73..00000000000
--- a/testing/mochitest/tests/test_cancelFullScreen.html
+++ /dev/null
@@ -1,52 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<head>
-  <title>Test for Bug 728893</title>
-  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <script type="text/javascript" src="/tests/SimpleTest/EventUtils.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
-</head>
-<body onload="start()">
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=728893">
-  Mozilla Bug
-</a>
-<div id="div">
-</div>
-<pre id="test">
-<script class="testbody" type="text/javascript">
-
-  /** Test for Bug 728893
-      Checks if SimpleTest.finish cancels fullscreen mode
-      The assertion happens after calling SimpleTest.finish
-      Running the test without the harness won't work
-  **/
-
-  SpecialPowers.setBoolPref("full-screen-api.enabled", true);
-  SpecialPowers.setBoolPref("full-screen-api.allow-trusted-requests-only",
-                                 false);
-
-  SimpleTest.waitForExplicitFinish();
-
-  var div = document.getElementById("div");
-
-  document.addEventListener("mozfullscreenchange", function (e) {
-    if (document.mozFullScreenElement === div) {
-      ok(true, "Calling SimpleTest.finish");
-      SimpleTest.finish();
-    }
-    else {
-      is(false, document.mozFullScreen,
-        "SimpleTest.finish should cancel fullscreen mode");
-    }
-  }, false);
-
-  function start() {
-    SimpleTest.waitForFocus(function() {
-      div.mozRequestFullScreen();
-    });
-  }
-
-</script>
-</pre>
-</body>
-</html>
\ No newline at end of file
