Bug 1482351 - Add placeholder for calendar preferences, and remove it if Lightning is not enabled. r=aceman,MakeMyDay

calendar/lightning/content/messenger-overlay-preferences.js

@@ -16,13 +16,8 @@ var gLightningPane = {
         ltnPrefs.addEventListener("select", gLightningPane.tabSelectionChanged.bind(this));
         this.mInitialized = true;
 
-        let prefTab = document.documentElement;
-        let lightningButton = prefTab._makePaneButton(document.getElementById("paneLightning"));
-        let advancedButton = document.querySelector('#category-box radio[pane="paneAdvanced"]');
-        advancedButton.parentNode.insertBefore(lightningButton, advancedButton);
-
-        // We probably messed this up just by existing. Fix it.
-        prefTab._paneDeck.selectedIndex = prefTab._selector.selectedIndex;
+        let categoryButton = document.querySelector('#category-box radio[pane="paneLightning"]');
+        categoryButton.label = document.getElementById("paneLightning").label;
 
         let elements = document.querySelectorAll("#paneLightning preference");
         for (let element of elements) {

mail/components/preferences/aboutPreferences.xul

@@ -52,5 +52,6 @@
 #include privacy.inc.xul
 #include security.inc.xul
 #include applications.inc.xul
+  <prefpane id="paneLightning"/>
 #include advanced.inc.xul
 </preftab>

mail/components/preferences/preferences.js

@@ -5,6 +5,7 @@
 ChromeUtils.import("resource://gre/modules/Services.jsm");
 ChromeUtils.import("resource://gre/modules/AppConstants.jsm");
 ChromeUtils.import("resource:///modules/MailServices.jsm");
+ChromeUtils.import("resource:///modules/extensionSupport.jsm");
 
 window.addEventListener("load", function() {
   let prefWindow = document.getElementById("MailPreferences");
@@ -15,6 +16,13 @@ window.addEventListener("load", function() {
       prefWindow.showPane(document.getElementById("paneGeneral"));
     radio.hidden = true;
   }
+  if (!ExtensionSupport.loadedLegacyExtensions.has("{e2fda1a4-762b-4020-b5ad-a41df1933103}")) {
+    let radio =
+      document.getAnonymousElementByAttribute(prefWindow, "pane", "paneLightning");
+    if (radio.selected)
+      prefWindow.showPane(document.getElementById("paneGeneral"));
+    radio.hidden = true;
+  }
 });
 
 /**