diff --git a/.prettierignore b/.prettierignore
index ab47dfa7c55b..18f671cedf10 100644
--- a/.prettierignore
+++ b/.prettierignore
@@ -234,7 +234,6 @@ docshell/test/iframesandbox/test_child_navigation_by_location.html
 docshell/test/mochitest/bug529119-window.html
 docshell/test/mochitest/test_bug387979.html
 docshell/test/mochitest/test_bug509055.html
-docshell/test/mochitest/test_bug511449.html
 docshell/test/mochitest/test_bug530396.html
 docshell/test/mochitest/test_forceinheritprincipal_overrule_owner.html
 docshell/test/navigation/file_triggeringprincipal_frame_1.html
diff --git a/docshell/test/mochitest/file_bug511449.html b/docshell/test/mochitest/file_bug511449.html
deleted file mode 100644
index 637732dbbf57..000000000000
--- a/docshell/test/mochitest/file_bug511449.html
+++ /dev/null
@@ -1,6 +0,0 @@
-<!DOCTYPE HTML>
-<title>Used in test for bug 511449</title>
-<input type="text" id="input">
-<script type="text/javascript">
-  document.getElementById("input").focus();
-</script>
diff --git a/docshell/test/mochitest/mochitest.toml b/docshell/test/mochitest/mochitest.toml
index 8d593c9e367c..93c1d1f9b1cb 100644
--- a/docshell/test/mochitest/mochitest.toml
+++ b/docshell/test/mochitest/mochitest.toml
@@ -78,15 +78,6 @@ skip-if = ["true"] # Disabled for too many intermittent failures (bug 719186)
 
 ["test_bug509055.html"]
 
-["test_bug511449.html"]
-skip-if = [
-  "os == 'win'",
-  "os == 'linux'",
-  "os == 'android'",
-  "headless", # Headless: bug 1410525
-]
-support-files = ["file_bug511449.html"]
-
 ["test_bug529119-1.html"]
 
 ["test_bug529119-2.html"]
diff --git a/docshell/test/mochitest/test_bug511449.html b/docshell/test/mochitest/test_bug511449.html
deleted file mode 100644
index da95909d1cb7..000000000000
--- a/docshell/test/mochitest/test_bug511449.html
+++ /dev/null
@@ -1,56 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=511449
--->
-<head>
-  <title>Test for Bug 511449</title>
-  <script src="/tests/SimpleTest/SimpleTest.js"></script>
-  <script src="/tests/SimpleTest/EventUtils.js"></script>
-  <script src="/tests/SimpleTest/NativeKeyCodes.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=511449">Mozilla Bug 511449</a>
-<p id="display"></p>
-<div id="status"></div>
-<div id="content">
-</div>
-<input type="text" id="input">
-<pre id="test">
-<script type="application/javascript">
-
-/** Test for Bug 511449 */
-
-SimpleTest.waitForExplicitFinish();
-SimpleTest.requestFlakyTimeout("untriaged");
-window.addEventListener("load", runTest);
-
-var win = null;
-
-function runTest() {
-  document.getElementById("input").focus();
-  win = window.open("file_bug511449.html", "");
-  SimpleTest.waitForFocus(runNextTest, win);
-}
-
-function runNextTest() {
-  var didClose = false;
-  win.onunload = function() {
-    didClose = true;
-  };
-  synthesizeNativeKey(KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_W, {metaKey: 1}, "w", "w");
-
-  setTimeout(function() {
-    ok(didClose, "Cmd+W should have closed the tab");
-    if (!didClose) {
-      win.close();
-    }
-    SimpleTest.finish();
-  }, 1000);
-}
-
-</script>
-
-</body>
-</html>
diff --git a/docshell/test/moz.build b/docshell/test/moz.build
index 0cdf1633c19c..36113f295cde 100644
--- a/docshell/test/moz.build
+++ b/docshell/test/moz.build
@@ -74,9 +74,6 @@ with Files("mochitest/*402210*"):
 with Files("mochitest/*509055*"):
     BUG_COMPONENT = ("Firefox", "Bookmarks & History")
 
-with Files("mochitest/*511449*"):
-    BUG_COMPONENT = ("Core", "Widget: Cocoa")
-
 with Files("mochitest/*551225*"):
     BUG_COMPONENT = ("Core", "DOM: Core & HTML")
 
