Index: gc_lang/fr/mailext/content/overlay.js
==================================================================
--- gc_lang/fr/mailext/content/overlay.js
+++ gc_lang/fr/mailext/content/overlay.js
@@ -7,11 +7,11 @@
 const Ci = Components.interfaces;
 //const Cu = Components.utils;
 //const { require } = Cu.import("resource://gre/modules/commonjs/toolkit/require.js", {});
 
 const { BasePromiseWorker } = ChromeUtils.import('resource://gre/modules/PromiseWorker.jsm', {});
-const prefs = Cc["@mozilla.org/preferences-service;1"].getService(Ci.nsIPrefService).getBranch("extensions.grammarchecker.");
+const xGrammalectePrefs = Cc["@mozilla.org/preferences-service;1"].getService(Ci.nsIPrefService).getBranch("extensions.grammarchecker.");
 
 //const text = require("resource://grammalecte/text.js");
 //const tf = require("resource://grammalecte/fr/textformatter.js");
 
 
@@ -37,24 +37,24 @@
         if (this.xGCEWorker === null) {
             // Grammar checker
             console.log('Loading Grammalecte');
             this.xGCEWorker = new BasePromiseWorker('chrome://promiseworker/content/gce_worker.js');
             let that = this;
-            let xPromise = this.xGCEWorker.post('loadGrammarChecker', [prefs.getCharPref("sGCOptions"), "Thunderbird"]);
+            let xPromise = this.xGCEWorker.post('loadGrammarChecker', [xGrammalectePrefs.getCharPref("sGCOptions"), "Thunderbird"]);
             xPromise.then(
                 function (aVal) {
                     console.log(aVal);
-                    prefs.setCharPref("sGCOptions", aVal);
+                    xGrammalectePrefs.setCharPref("sGCOptions", aVal);
                     // spelling dictionary
-                    if (prefs.getCharPref("sMainDicName")) {
-                        let sMainDicName = prefs.getCharPref("sMainDicName");
+                    if (xGrammalectePrefs.getCharPref("sMainDicName")) {
+                        let sMainDicName = xGrammalectePrefs.getCharPref("sMainDicName");
                         if (sMainDicName == "fr-classic.json" || sMainDicName == "fr-reform.json") {
                             that.xGCEWorker.post("setDictionary", ["main", sMainDicName]);
                         }
                     }
                     // personal dictionary
-                    if (prefs.getBoolPref("bPersonalDictionary")) {
+                    if (xGrammalectePrefs.getBoolPref("bPersonalDictionary")) {
                         let sDicJSON = oFileHandler.loadFile("fr.personal.json");
                         if (sDicJSON) {
                             that.xGCEWorker.post('setDictionary', ["personal", sDicJSON]);
                         }
                     }
@@ -97,15 +97,15 @@
             function (aCaught) { console.log('Promise Error', aCaught); }
         );
     },
     setOptions: function () {
         console.log('Set options');
-        let xPromise = this.xGCEWorker.post('setOptions', [prefs.getCharPref("sGCOptions")]);
+        let xPromise = this.xGCEWorker.post('setOptions', [xGrammalectePrefs.getCharPref("sGCOptions")]);
         xPromise.then(
             function (aVal) {
                 console.log(aVal);
-                prefs.setCharPref("sGCOptions", aVal);
+                xGrammalectePrefs.setCharPref("sGCOptions", aVal);
             },
             function (aReason) { console.log('Promise rejected', aReason); }
         ).catch(
             function (aCaught) { console.log('Promise Error', aCaught); }
         );
@@ -113,11 +113,11 @@
     resetOptions: function () {
         let xPromise = this.xGCEWorker.post('resetOptions');
         xPromise.then(
             function (aVal) {
                 console.log(aVal);
-                prefs.setCharPref("sGCOptions", aVal);
+                xGrammalectePrefs.setCharPref("sGCOptions", aVal);
             },
             function (aReason) { console.log('Promise rejected', aReason); }
         ).catch(
             function (aCaught) { console.log('Promise Error', aCaught); }
         );
@@ -444,11 +444,11 @@
         let that = this;
         let xPromise = this.xGCEWorker.post('getDefaultOptions');
         xPromise.then(
             function (aVal) {
                 console.log(aVal);
-                prefs.setCharPref("sGCDefaultOptions", aVal);
+                xGrammalectePrefs.setCharPref("sGCDefaultOptions", aVal);
             },
             function (aReason) { console.log('Promise rejected', aReason); }
         ).catch(
             function (aCaught) { console.log('Promise Error', aCaught); }
         ).then(
@@ -485,11 +485,11 @@
 var oTextFormatter = {
     init: function () {
         try {
             this.closePanel();
             this.listen();
-            let sTFOptions = prefs.getCharPref("sTFOptions");
+            let sTFOptions = xGrammalectePrefs.getCharPref("sTFOptions");
             if (sTFOptions !== "") {
                 this.setOptionsInPanel(JSON.parse(sTFOptions));
                 this.resetProgressBar();
             } else {
                 this.reset();
@@ -529,11 +529,11 @@
         let oOptions = {};
         for (let xNode of document.getElementsByClassName("option")) {
             oOptions[xNode.id] = xNode.checked;
         }
         //console.log("save options: " + JSON.stringify(oOptions));
-        prefs.setCharPref("sTFOptions", JSON.stringify(oOptions));
+        xGrammalectePrefs.setCharPref("sTFOptions", JSON.stringify(oOptions));
     },
     setOptionsInPanel: function (oOptions) {
         for (let sOptName in oOptions) {
             //console.log(sOptName + ":" + oOptions[sOptName]);
             if (document.getElementById(sOptName) !== null) {