diff --git a/toolkit/content/tests/chrome/chrome.ini b/toolkit/content/tests/chrome/chrome.ini
index 860294c0c56e..f14fbc876449 100644
--- a/toolkit/content/tests/chrome/chrome.ini
+++ b/toolkit/content/tests/chrome/chrome.ini
@@ -114,6 +114,8 @@ subsuite = clipboard
 [test_labelcontrol.xul]
 [test_largemenu.xul]
 skip-if = os == 'linux' && !debug # Bug 1207174
+[test_maximized_persist.xul]
+support-files = window_maximized_persist.xul
 [test_menu.xul]
 [test_menu_anchored.xul]
 [test_menu_withcapture.xul]
diff --git a/toolkit/content/tests/chrome/test_maximized_persist.xul b/toolkit/content/tests/chrome/test_maximized_persist.xul
new file mode 100644
index 000000000000..be1f7f3c897b
--- /dev/null
+++ b/toolkit/content/tests/chrome/test_maximized_persist.xul
@@ -0,0 +1,148 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css" type="text/css"?>
+<window title="Window Open Test"
+        onload="runTest()"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+<script type="application/javascript"
+        src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+<script type="application/javascript"
+        src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"/>
+<script class="testbody" type="application/javascript"><![CDATA[
+  SimpleTest.waitForExplicitFinish();
+  const WIDTH = 300;
+  const HEIGHT = 300;
+
+  function promiseMessage(msg) {
+    info(`wait for message "${msg}"`);
+    return new Promise(resolve => {
+      function listener(evt) {
+        info(`got message "${evt.data}"`);
+        if (evt.data == msg) {
+          window.removeEventListener("message", listener);
+          resolve();
+        }
+      }
+      window.addEventListener("message", listener);
+    });
+  }
+
+  function openWindow(features = "") {
+    return window.openDialog("window_maximized_persist.xul",
+                             null, "chrome,dialog=no,all," + features);
+  }
+
+  function checkWindow(msg, win, sizemode, width, height) {
+    is(win.windowState, sizemode, "sizemode should match " + msg);
+    if (sizemode == win.STATE_NORMAL) {
+      is(win.innerWidth, width, "width should match " + msg);
+      is(win.innerHeight, height, "height should match " + msg);
+    }
+  }
+
+  function todoCheckWindow(msg, win, sizemode) {
+    todo_is(win.windowState, sizemode, "sizemode should match " + msg);
+  }
+
+  // Persistence of "sizemode" is delayed to 500ms after it's changed.
+  // See SIZE_PERSISTENCE_TIMEOUT in nsWebShellWindow.cpp.
+  // We wait for 1000ms to ensure that it is actually persisted.
+  // We can also wait for condition that XULStore does have the value
+  // set, but that way we cannot test the cases where we don't expect
+  // persistence to happen.
+  function waitForSizeModePersisted() {
+    return new Promise(resolve => {
+      setTimeout(resolve, 1000);
+    });
+  }
+
+  async function changeSizeMode(func) {
+    let promiseSizeModeChange = promiseMessage("sizemodechange");
+    func();
+    await promiseSizeModeChange;
+    await waitForSizeModePersisted();
+  }
+
+  async function runTest() {
+    let win = openWindow();
+    await SimpleTest.promiseFocus(win);
+
+    // Check the default state.
+    const chrome_url = win.location.href;
+    checkWindow("when open initially", win, win.STATE_NORMAL, WIDTH, HEIGHT);
+    const widthDiff = win.outerWidth - win.innerWidth;
+    const heightDiff = win.outerHeight - win.innerHeight;
+    // Maximize the window.
+    await changeSizeMode(() => win.maximize());
+    checkWindow("after maximize window", win, win.STATE_MAXIMIZED);
+    win.close();
+
+    // Open a new window to check persisted sizemode.
+    win = openWindow();
+    await SimpleTest.promiseFocus(win);
+    checkWindow("when reopen to maximized", win, win.STATE_MAXIMIZED);
+    // Restore the window.
+    if (win.windowState == win.STATE_MAXIMIZED) {
+      await changeSizeMode(() => win.restore());
+    }
+    checkWindow("after restore window", win, win.STATE_NORMAL, WIDTH, HEIGHT);
+    win.close();
+
+    // Open a new window again to check persisted sizemode.
+    win = openWindow();
+    await SimpleTest.promiseFocus(win);
+    checkWindow("when reopen to normal", win, win.STATE_NORMAL, WIDTH, HEIGHT);
+    // And maximize the window again for next test.
+    await changeSizeMode(() => win.maximize());
+    win.close();
+
+    // Linux doesn't seem to persist sizemode across opening window
+    // with specified size, so mark it expected fail for now.
+    let todo = navigator.platform.includes('Linux');
+    let checkWindowMayFail = todo ? todoCheckWindow : checkWindow;
+
+    // Open a new window with size specified.
+    win = openWindow("width=400,height=400");
+    await SimpleTest.promiseFocus(win);
+    checkWindow("when reopen with size", win, win.STATE_NORMAL, 400, 400);
+    await waitForSizeModePersisted();
+    win.close();
+
+    // Open a new window without size specified.
+    // The window opened before should not change persisted sizemode.
+    win = openWindow();
+    await SimpleTest.promiseFocus(win);
+    checkWindowMayFail("when reopen without size", win, win.STATE_MAXIMIZED);
+    win.close();
+
+    // Open a new window with sizing synchronously.
+    win = openWindow();
+    win.resizeTo(500 + widthDiff, 500 + heightDiff);
+    await SimpleTest.promiseFocus(win);
+    checkWindow("when sized synchronously", win, win.STATE_NORMAL, 500, 500);
+    await waitForSizeModePersisted();
+    win.close();
+
+    // Open a new window without any sizing.
+    // The window opened before should not change persisted sizemode.
+    win = openWindow();
+    await SimpleTest.promiseFocus(win);
+    checkWindowMayFail("when reopen without sizing", win, win.STATE_MAXIMIZED);
+    win.close();
+
+    // Clean up the XUL store for the given window.
+    let XULStore = Cc["@mozilla.org/xul/xulstore;1"].getService(Ci.nsIXULStore);
+    XULStore.removeDocument(chrome_url);
+
+    SimpleTest.finish();
+  }
+]]></script>
+<body xmlns="http://www.w3.org/1999/xhtml">
+<p id="display">
+</p>
+<div id="content" style="display: none">
+</div>
+<pre id="test">
+</pre>
+</body>
+</window>
diff --git a/toolkit/content/tests/chrome/window_maximized_persist.xul b/toolkit/content/tests/chrome/window_maximized_persist.xul
new file mode 100644
index 000000000000..483a072fc791
--- /dev/null
+++ b/toolkit/content/tests/chrome/window_maximized_persist.xul
@@ -0,0 +1,15 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<window title="Window Open Test"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        height="300"
+        width="300"
+        sizemode="normal"
+        id="window"
+        persist="height width sizemode">
+<script type="application/javascript"><![CDATA[
+  window.addEventListener("sizemodechange", evt => {
+    opener.postMessage("sizemodechange", "*");
+  });
+]]></script>
+</window>