Add logic for selecting existing settings tabs

src/main.js

@@ -14,6 +14,14 @@
  */
 const BROWSER_NAME = 'Orfox';
 
+/**
+ * The location of the settings page.
+ *
+ * @constant SETTINGS_URI
+ * @type {String}
+ */
+const SETTINGS_URI = 'chrome://tor-browser-settings/content/settings.html';
+
 /**
  * Application settings module.
  *
@@ -61,12 +69,32 @@ exports.main = function () {
         name: _('settings_label', BROWSER_NAME),
         callback: function () {
 
-            let tabBrowser = chromeWindow.BrowserApp;
+            let tabBrowser, settingsTab;
+
+            tabBrowser = chromeWindow.BrowserApp;
+            settingsTab = null;
 
-            tabBrowser.addTab('chrome://tor-browser-settings/content/settings.html', {
-                selected: true,
-                parentId: tabBrowser.selectedTab.id
+            tabBrowser.tabs.some(function (tab) {
+
+                if (tab.browser.currentURI.spec === SETTINGS_URI) {
+
+                    settingsTab = tab;
+                    return true;
+                }
+
+                return false;
             });
+
+            if (settingsTab === null) {
+
+                tabBrowser.addTab(SETTINGS_URI, {
+                    selected: true,
+                    parentId: tabBrowser.selectedTab.id
+                });
+
+            } else {
+                tabBrowser.selectTab(settingsTab);
+            }
         }
     });
 };

src/settings.js

@@ -16,6 +16,14 @@
  */
 const BROWSER_NAME = 'Orfox';
 
+/**
+ * The location of the settings page.
+ *
+ * @constant SETTINGS_URI
+ * @type {String}
+ */
+const SETTINGS_URI = 'chrome://tor-browser-settings/content/settings.html';
+
 /**
  * Can be used to get localization entries by key name.
  *
@@ -50,7 +58,7 @@ var settings = require('sdk/simple-prefs').prefs;
 exports.initialize = function () {
 
     pageMod.PageMod({
-        include: 'chrome://tor-browser-settings/content/settings.html',
+        include: SETTINGS_URI,
         contentScriptFile: self.data.url('content-scripts/settings.js'),
         contentScriptWhen: 'ready',
         onAttach: startListening