--- a/browser/components/customizableui/content/panelUI.js
+++ b/browser/components/customizableui/content/panelUI.js
@@ -55,17 +55,43 @@ const PanelUI = {
 
     this.menuButton.addEventListener("mousedown", this);
     this.menuButton.addEventListener("keypress", this);
     this._overlayScrollListenerBoundFn = this._overlayScrollListener.bind(this);
 
     Services.obs.addObserver(this, "fullscreen-nav-toolbox");
     Services.obs.addObserver(this, "appMenu-notifications");
 
-    window.addEventListener("fullscreen", this);
+    XPCOMUtils.defineLazyPreferenceGetter(this, "autoHideToolbarInFullScreen",
+      "browser.fullscreen.autohide", false, (pref, previousValue, newValue) => {
+        // On OSX, or with autohide preffed off, MozDOMFullscreen is the only
+        // event we care about, since fullscreen should behave just like non
+        // fullscreen. Otherwise, we don't want to listen to these because
+        // we'd just be spamming ourselves with both of them whenever a user
+        // opened a video.
+        if (newValue) {
+          window.removeEventListener("MozDOMFullscreen:Entered", this);
+          window.removeEventListener("MozDOMFullscreen:Exited", this);
+          window.addEventListener("fullscreen", this);
+        } else {
+          window.addEventListener("MozDOMFullscreen:Entered", this);
+          window.addEventListener("MozDOMFullscreen:Exited", this);
+          window.removeEventListener("fullscreen", this);
+        }
+
+        this._updateNotifications(false);
+      }, autoHidePref => autoHidePref && Services.appinfo.OS !== "Darwin");
+
+    if (this.autoHideToolbarInFullScreen) {
+      window.addEventListener("fullscreen", this);
+    } else {
+      window.addEventListener("MozDOMFullscreen:Entered", this);
+      window.addEventListener("MozDOMFullscreen:Exited", this);
+    }
+
     window.addEventListener("activate", this);
     window.matchMedia("(-moz-overlay-scrollbars)").addListener(this._overlayScrollListenerBoundFn);
     CustomizableUI.addListener(this);
 
     for (let event of this.kEvents) {
       this.notificationPanel.addEventListener(event, this);
     }
 
@@ -170,16 +196,18 @@ const PanelUI = {
     this._removeEventListeners();
     for (let event of this.kEvents) {
       this.notificationPanel.removeEventListener(event, this);
     }
 
     Services.obs.removeObserver(this, "fullscreen-nav-toolbox");
     Services.obs.removeObserver(this, "appMenu-notifications");
 
+    window.removeEventListener("MozDOMFullscreen:Entered", this);
+    window.removeEventListener("MozDOMFullscreen:Exited", this);
     window.removeEventListener("fullscreen", this);
     window.removeEventListener("activate", this);
     this.menuButton.removeEventListener("mousedown", this);
     this.menuButton.removeEventListener("keypress", this);
     window.matchMedia("(-moz-overlay-scrollbars)").removeListener(this._overlayScrollListenerBoundFn);
     CustomizableUI.removeListener(this);
     this._overlayScrollListenerBoundFn = null;
   },
@@ -321,16 +349,18 @@ const PanelUI = {
         break;
       case "mousedown":
         if (aEvent.button == 0)
           this.toggle(aEvent);
         break;
       case "keypress":
         this.toggle(aEvent);
         break;
+      case "MozDOMFullscreen:Entered":
+      case "MozDOMFullscreen:Exited":
       case "fullscreen":
       case "activate":
         this._updateNotifications();
         break;
     }
   },
 
   get isReady() {
@@ -739,20 +769,18 @@ const PanelUI = {
       // since we don't want their doorhangers competing for attention
       doorhangers.forEach(n => { n.dismissed = true; })
       this._hidePopup();
       this._clearBadge();
       if (!notifications[0].options.badgeOnly) {
         this._showBannerItem(notifications[0]);
       }
     } else if (doorhangers.length > 0) {
-      let autoHideFullScreen = Services.prefs.getBoolPref("browser.fullscreen.autohide", false) &&
-                               Services.appinfo.OS !== "Darwin";
       // Only show the doorhanger if the window is focused and not fullscreen
-      if ((window.fullScreen && autoHideFullScreen) || Services.focus.activeWindow !== window) {
+      if ((window.fullScreen && this.autoHideToolbarInFullScreen) || Services.focus.activeWindow !== window) {
         this._hidePopup();
         this._showBadge(doorhangers[0]);
         this._showBannerItem(doorhangers[0]);
       } else {
         this._clearBadge();
         this._showNotificationPanel(doorhangers[0]);
       }
     } else {

--- a/browser/components/customizableui/test/browser.ini
+++ b/browser/components/customizableui/test/browser.ini
@@ -151,16 +151,18 @@ skip-if = os == "mac"
 [browser_exit_background_customize_mode.js]
 [browser_overflow_use_subviews.js]
 [browser_panel_keyboard_navigation.js]
 [browser_panel_toggle.js]
 [browser_panelUINotifications.js]
 [browser_panelUINotifications_fullscreen.js]
 tags = fullscreen
 skip-if = os == "mac"
+[browser_panelUINotifications_fullscreen_noAutoHideToolbar.js]
+tags = fullscreen
 [browser_panelUINotifications_multiWindow.js]
 [browser_switch_to_customize_mode.js]
 [browser_synced_tabs_menu.js]
 [browser_check_tooltips_in_navbar.js]
 [browser_editcontrols_update.js]
 subsuite = clipboard
 [browser_photon_customization_context_menus.js]
 [browser_remote_tabs_button.js]

new file mode 100644
--- /dev/null
+++ b/browser/components/customizableui/test/browser_panelUINotifications_fullscreen_noAutoHideToolbar.js
@@ -0,0 +1,57 @@
+"use strict";
+
+Cu.import("resource://gre/modules/AppMenuNotifications.jsm");
+
+add_task(async function testFullscreen() {
+  if (Services.appinfo.OS !== "Darwin") {
+    await SpecialPowers.pushPrefEnv({
+      set: [
+        ["browser.fullscreen.autohide", false],
+      ]});
+  }
+
+  is(PanelUI.notificationPanel.state, "closed", "update-manual doorhanger is closed.");
+  let mainActionCalled = false;
+  let mainAction = {
+    callback: () => { mainActionCalled = true; }
+  };
+  AppMenuNotifications.showNotification("update-manual", mainAction);
+
+  isnot(PanelUI.notificationPanel.state, "closed", "update-manual doorhanger is showing.");
+  let notifications = [...PanelUI.notificationPanel.children].filter(n => !n.hidden);
+  is(notifications.length, 1, "PanelUI doorhanger is only displaying one notification.");
+  let doorhanger = notifications[0];
+  is(doorhanger.id, "appMenu-update-manual-notification", "PanelUI is displaying the update-manual notification.");
+
+  let fullscreenPromise = BrowserTestUtils.waitForEvent(window, "fullscreen");
+  EventUtils.synthesizeKey("VK_F11", {});
+  await fullscreenPromise;
+  isnot(PanelUI.notificationPanel.state, "closed", "update-manual doorhanger is still showing after entering fullscreen.");
+
+  let popuphiddenPromise = BrowserTestUtils.waitForEvent(PanelUI.notificationPanel, "popuphidden");
+  await ContentTask.spawn(gBrowser.selectedBrowser, {}, async () => {
+    content.document.documentElement.requestFullscreen();
+  });
+  await popuphiddenPromise;
+  await new Promise(executeSoon);
+  is(PanelUI.notificationPanel.state, "closed", "update-manual doorhanger is hidden after entering DOM fullscreen.");
+
+  let popupshownPromise = BrowserTestUtils.waitForEvent(PanelUI.notificationPanel, "popupshown");
+  await ContentTask.spawn(gBrowser.selectedBrowser, {}, async () => {
+    content.document.exitFullscreen();
+  });
+  await popupshownPromise;
+  await new Promise(executeSoon);
+  isnot(PanelUI.notificationPanel.state, "closed", "update-manual doorhanger is shown after exiting DOM fullscreen.");
+  isnot(PanelUI.menuButton.getAttribute("badge-status"), "update-manual", "Badge is not displaying on PanelUI button.");
+
+  let mainActionButton = document.getAnonymousElementByAttribute(doorhanger, "anonid", "button");
+  mainActionButton.click();
+  ok(mainActionCalled, "Main action callback was called");
+  is(PanelUI.notificationPanel.state, "closed", "update-manual doorhanger is closed.");
+  is(PanelUI.menuButton.hasAttribute("badge-status"), false, "Should not have a badge status");
+
+  fullscreenPromise = BrowserTestUtils.waitForEvent(window, "fullscreen");
+  EventUtils.synthesizeKey("VK_F11", {});
+  await fullscreenPromise;
+});