diff --git a/TODO b/TODO
index 5ae95ff..861ada5 100644
--- a/TODO
+++ b/TODO
@@ -1,8 +1,6 @@
 TODO
 ----
 
-* no Chat in Seamonkey !
-
 WONTFIX
 -------
 
diff --git a/src/modules/FiretrayHandler.jsm b/src/modules/FiretrayHandler.jsm
index af7226d..0e7d83f 100644
--- a/src/modules/FiretrayHandler.jsm
+++ b/src/modules/FiretrayHandler.jsm
@@ -33,6 +33,7 @@ firetray.Handler = {
   initialized: false,
   inBrowserApp: false,
   inMailApp: false,
+  appHasChat: false,
   appStarted: false,
   windows: {},
   windowsCount: 0,
@@ -59,7 +60,7 @@ firetray.Handler = {
 
     // version checked during install, so we shouldn't need to care
     let xulVer = Services.appinfo.platformVersion; // Services.vc.compare(xulVer,"2.0a")>=0
-    log.debug("OS=" + this.runtimeOS + ", ABI=" + this.runtimeABI + ", XULrunner=" + xulVer);
+    log.info("OS=" + this.runtimeOS + ", ABI=" + this.runtimeABI + ", XULrunner=" + xulVer);
     switch (this.runtimeOS) {
     case "Linux":
       Cu.import("resource://firetray/linux/FiretrayStatusIcon.jsm");
@@ -76,7 +77,9 @@ firetray.Handler = {
       this.inMailApp = true;
     if (this.appId === FIRETRAY_FIREFOX_ID || this.appId === FIRETRAY_SEAMONKEY_ID)
       this.inBrowserApp = true;
-    log.debug('inMailApp: '+this.inMailApp+', inBrowserApp: '+this.inBrowserApp);
+    if (this.appId === FIRETRAY_THUNDERBIRD_ID && Services.vc.compare(xulVer,"15.0")>=0)
+      this.appHasChat = true;
+    log.info('inMailApp='+this.inMailApp+', inBrowserApp='+this.inBrowserApp+', appHasChat='+this.appHasChat);
 
     this.appStartupTopic = this.getAppStartupTopic(this.appId);
 
diff --git a/src/modules/FiretrayMessaging.jsm b/src/modules/FiretrayMessaging.jsm
index 742e131..84e425b 100644
--- a/src/modules/FiretrayMessaging.jsm
+++ b/src/modules/FiretrayMessaging.jsm
@@ -10,7 +10,6 @@ Cu.import("resource:///modules/mailServices.js");
 Cu.import("resource://gre/modules/Services.jsm");
 Cu.import("resource://gre/modules/PluralForm.jsm");
 Cu.import("resource://firetray/commons.js");
-Cu.import("resource://firetray/FiretrayChat.jsm");
 
 const FLDRS_UNINTERESTING = {
   Archive:   Ci.nsMsgFolderFlags.Archive,
@@ -47,10 +46,13 @@ firetray.Messaging = {
     MailServices.mailSession.AddFolderListener(that.mailSessionListener,
                                                that.mailSessionListener.notificationFlags);
 
-    if (Services.prefs.getBoolPref("mail.chat.enabled") &&
+    if (firetray.Handler.appHasChat &&
+        Services.prefs.getBoolPref("mail.chat.enabled") &&
         firetray.Utils.prefService.getBoolPref("chat_icon_enable") &&
-        this.existsChatAccount())
+        this.existsChatAccount()) {
+      Cu.import("resource://firetray/FiretrayChat.jsm");
       firetray.Chat.init();
+    }
 
     this.initialized = true;
   },
@@ -59,7 +61,7 @@ firetray.Messaging = {
     if (!this.initialized) return;
     log.debug("Disabling Messaging");
 
-    if (firetray.hasOwnProperty('Chat')) firetray.Chat.shutdown();
+    if (firetray.Handler.appHasChat) firetray.Chat.shutdown();
 
     MailServices.mailSession.RemoveFolderListener(this.mailSessionListener);
 
diff --git a/src/modules/linux/FiretrayWindow.jsm b/src/modules/linux/FiretrayWindow.jsm
index 6c43ac3..1f3163f 100644
--- a/src/modules/linux/FiretrayWindow.jsm
+++ b/src/modules/linux/FiretrayWindow.jsm
@@ -588,7 +588,7 @@ firetray.Handler.registerWindow = function(win) {
     this.windows[xid].filterWindowCb = gdk.GdkFilterFunc_t(firetray.Window.filterWindow);
     gdk.gdk_window_add_filter(gdkWin, this.windows[xid].filterWindowCb, null);
 
-    if (firetray.Handler.inMailApp && firetray.Chat.initialized) { // missing import ok
+    if (firetray.Handler.appHasChat && firetray.Chat.initialized) { // missing import ok
       Cu.import("resource://firetray/linux/FiretrayChatStatusIcon.jsm");
       firetray.ChatStatusIcon.attachOnFocusInCallback(xid);
     }