diff --git a/src/chrome/content/overlay.js b/src/chrome/content/overlay.js
index 34b19af..4ba5aaf 100644
--- a/src/chrome/content/overlay.js
+++ b/src/chrome/content/overlay.js
@@ -1,118 +1,11 @@
 /* -*- Mode: js2; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 
-Components.utils.import("resource://gre/modules/Services.jsm");
-Components.utils.import("resource://gre/modules/ctypes.jsm");
-Components.utils.import("resource://moztray/LibGObject.jsm");
-Components.utils.import("resource://moztray/LibGtkStatusIcon.jsm");
 Components.utils.import("resource://moztray/commons.js");
-
-const MOZT_ICON_DIR = "chrome/skin/";
-const MOZT_ICON_SUFFIX = "32.png";
-
-
-/**
- * mozt namespace.
- */
-if ("undefined" == typeof(mozt)) {
-  var mozt = {};
-};
-
-mozt.Handler = {
-  _windowsHidden: false,
-
-  _getBaseWindow: function(win) {
-    var bw;
-    try { // thx Neil Deakin !!
-      bw = win.QueryInterface(Components.interfaces.nsIInterfaceRequestor)
-        .getInterface(Components.interfaces.nsIWebNavigation)
-        .QueryInterface(Components.interfaces.nsIDocShellTreeItem)
-        .treeOwner
-        .QueryInterface(Components.interfaces.nsIInterfaceRequestor)
-        .getInterface(Components.interfaces.nsIBaseWindow);
-    } catch (ex) {
-      bw = null;
-      setTimeout(function() {throw ex; }, 0);
-      // ignore no-interface exception
-    }
-    return bw;
-  },
-
-  _getAllWindows: function() {
-    mozt.Debug.debug("_getAllWindows");
-    var baseWindows = new Array();
-    var e = Services.wm.getEnumerator(null);
-    while (e.hasMoreElements()) {
-      var w = e.getNext();
-      baseWindows[baseWindows.length] = this._getBaseWindow(w);
-    }
-    return baseWindows;
-  },
-
-  /*
-   * might need to remember position...
-   * var outX = {}, outY = {}, outCX = {}, outCY = {};
-   * bw.getPositionAndSize(outX, outY, outCX, outCY);
-   * mozt.Debug.debug("pos: "
-   *                  + outX.value + ", "
-   *                  + outY.value + ", "
-   *                  + outCX.value + ", "
-   *                  + outCY.value
-   *                 );
-   */
-  showHideToTray: function(a1, a2, a3) {
-    mozt.Debug.debug("showHideToTray");
-
-    var baseWindows;
-    try {
-      baseWindows = this._getAllWindows();
-    } catch (x) {
-      mozt.Debug.debug(x);
-    }
-    mozt.Debug.debug("baseWindows: " + baseWindows.length);
-    for(var i=0; i<baseWindows.length; i++) {
-      var bw = baseWindows[i];
-
-      mozt.Debug.debug('isHidden: ' + this._windowsHidden);
-      mozt.Debug.debug("bw.visibility: " + bw.visibility);
-      try {
-        if (this._windowsHidden) {
-          bw.visibility = true;
-        } else {
-          bw.visibility = false;
-        }
-      } catch (x) {
-        mozt.Debug.debug(x);
-      }
-      mozt.Debug.debug("bw.visibility: " + bw.visibility);
-
-      mozt.Debug.debug("bw.title: " + bw.title);
-      mozt.Debug.debug("bw.parentNativeWindow: " + bw.parentNativeWindow);
-    }
-
-    if (this._windowsHidden) {
-      this._windowsHidden = false;
-    } else {
-      this._windowsHidden = true;
-    }
-
-  },
-
-}; // mozt.Handler
-
-
-var mozt_activateCb;            // pointer to JS function. should not be eaten
-                                // by GC ("Running global cleanup code from
-                                // study base classes" ?)
+Components.utils.import("resource://moztray/MoztHandler.jsm");
 
 mozt.Main = {
-  initialized: false,
 
   onLoad: function() {
-    if (this.initialized)
-      return true;              // prevent creating multiple tray icon
-
-    mozt.Debug.debug('initialized: ' + this.initialized);
-
     // initialization code
     this.strings = document.getElementById("moztray-strings");
 
@@ -126,67 +19,10 @@ mozt.Main = {
       return false;
     }
 
-    try {
-
-      // instanciate tray icon
-      LibGtkStatusIcon.init();
-      this.tray_icon  = LibGtkStatusIcon.gtk_status_icon_new();
-      var mozApp = Services.appinfo.name.toLowerCase();
-      var iconFilename = MOZT_ICON_DIR + mozApp + MOZT_ICON_SUFFIX;
-      LibGtkStatusIcon.gtk_status_icon_set_from_file(this.tray_icon,
-                                                     iconFilename);
-
-      // set tooltip.
-      // TODO: produces:
-      // (firefox-bin:5302): Gdk-CRITICAL **: IA__gdk_window_get_root_coords: assertion `GDK_IS_WINDOW (window)' failed
-      // (thunderbird-bin:5380): Gdk-CRITICAL **: IA__gdk_window_get_root_coords: assertion `GDK_IS_WINDOW (window)' failed
-      LibGtkStatusIcon.gtk_status_icon_set_tooltip_text(this.tray_icon,
-                                                        mozApp);
-
-      LibGtkStatusIcon.shutdown();
-
-      // watch out for binding problems !
-      mozt_activateCb = LibGObject.GCallback_t(
-        function(){mozt.Handler.showHideToTray();});
-      LibGObject.g_signal_connect(this.tray_icon, "activate",
-                                  mozt_activateCb, null);
-
-    } catch (x) {
-      Components.utils.reportError(x);
-      return false;
-    }
-
-/*
-    try {
-      // Experimental stuff... needs
-      // Components.utils.import("resource://moztray/LibGdkWindow.js");
-
-      var gdkScreen = LibGdkWindow.GdkScreenGetDefault();
-      var tl = LibGdkWindow.GdkScreenGetToplevelWindows(gdkScreen);
-      mozt.Debug.debug(tl);
-
-      // gboolean            gdk_window_is_visible               (GdkWindow *window);
-      mozt_func = LibGObject.GFunc_t(mozt_funcGdkJS);
-      LibGObject.g_list_foreach(tl, mozt_func, null);
-      var gdkWinCount = LibGObject.g_list_length(tl);
-      mozt.Debug.debug('gdkWinCount: ' + gdkWinCount);
-
-      var pid = LibC.getpid();
-      mozt.Debug.debug(pid);
-
-      tl = LibGtkStatusIcon.gtk_window_list_toplevels();
-      mozt_func = LibGObject.GFunc_t(mozt_funcGtkJS);
-      LibGObject.g_list_foreach(tl, mozt_func, null);
-      var gtkWinCount = LibGObject.g_list_length(tl);
-      mozt.Debug.debug('gtkWinCount: ' + gtkWinCount);
-
-    } catch (x) {
-      mozt.Debug.debug(x);
-    }
-*/
+    if (!mozt.Handler.initialized)
+      mozt.Handler.init();
 
     mozt.Debug.debug('Moztray LOADED !');
-    this.initialized = true;
     return true;
   },
 
@@ -195,7 +31,7 @@ mozt.Main = {
     mozt.Utils.prefService.removeObserver("", this);
 
     mozt.Debug.debug('Moztray UNLOADED !');
-    this.initialized = false;
+    mozt.Handler.initialized = false;
   },
 
   observe: function(subject, topic, data) {
@@ -213,7 +49,6 @@ mozt.Main = {
 
 };
 
-
 // should be sufficient for a delayed Startup (no need for window.setTimeout())
 // https://developer.mozilla.org/en/Extensions/Performance_best_practices_in_extensions
 // https://developer.mozilla.org/en/XUL_School/JavaScript_Object_Management.html
diff --git a/src/modules/MoztHandler.jsm b/src/modules/MoztHandler.jsm
new file mode 100644
index 0000000..3a54477
--- /dev/null
+++ b/src/modules/MoztHandler.jsm
@@ -0,0 +1,183 @@
+/* -*- Mode: js2; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+
+var EXPORTED_SYMBOLS = [ "mozt" ];
+
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+const Cu = Components.utils;
+
+Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/ctypes.jsm");
+/* Cu.import("resource://moztray/LibC.jsm"); */
+Cu.import("resource://moztray/LibGObject.jsm");
+Cu.import("resource://moztray/LibGtkStatusIcon.jsm");
+Cu.import("resource://moztray/commons.js");
+
+const MOZT_ICON_DIR = "chrome/skin/";
+const MOZT_ICON_SUFFIX = "32.png";
+
+/**
+ * mozt namespace.
+ */
+if ("undefined" == typeof(mozt)) {
+  var mozt = {};
+};
+
+var mozt_activateCb;            // pointer to JS function. should not be eaten
+                                // by GC ("Running global cleanup code from
+                                // study base classes" ?)
+/**
+ * Singleton object for tray icon management
+ */
+// NOTE: modules work outside of the window scope. Unlike scripts in the
+// chrome, modules don't have access to objects such as window, document, or
+// other global functions
+// (https://developer.mozilla.org/en/XUL_School/JavaScript_Object_Management)
+mozt.Handler = {
+  initialized: false,
+
+  _windowsHidden: false,
+
+  _getBaseWindow: function(win) {
+    var bw;
+    try { // thx Neil Deakin !!
+      bw = win.QueryInterface(Components.interfaces.nsIInterfaceRequestor)
+        .getInterface(Components.interfaces.nsIWebNavigation)
+        .QueryInterface(Components.interfaces.nsIDocShellTreeItem)
+        .treeOwner
+        .QueryInterface(Components.interfaces.nsIInterfaceRequestor)
+        .getInterface(Components.interfaces.nsIBaseWindow);
+    } catch (ex) {
+      bw = null;
+      setTimeout(function() {throw ex; }, 0);
+      // ignore no-interface exception
+    }
+    return bw;
+  },
+
+  _getAllWindows: function() {
+    mozt.Debug.debug("_getAllWindows");
+    var baseWindows = new Array();
+    var e = Services.wm.getEnumerator(null);
+    while (e.hasMoreElements()) {
+      var w = e.getNext();
+      baseWindows[baseWindows.length] = this._getBaseWindow(w);
+    }
+    return baseWindows;
+  },
+
+  /*
+   * might need to remember position...
+   * var outX = {}, outY = {}, outCX = {}, outCY = {};
+   * bw.getPositionAndSize(outX, outY, outCX, outCY);
+   * mozt.Debug.debug("pos: "
+   *                  + outX.value + ", "
+   *                  + outY.value + ", "
+   *                  + outCX.value + ", "
+   *                  + outCY.value
+   *                 );
+   */
+  showHideToTray: function(a1, a2, a3) {
+    mozt.Debug.debug("showHideToTray");
+
+    var baseWindows;
+    try {
+      baseWindows = this._getAllWindows();
+    } catch (x) {
+      mozt.Debug.debug(x);
+    }
+    mozt.Debug.debug("baseWindows: " + baseWindows.length);
+    for(var i=0; i<baseWindows.length; i++) {
+      var bw = baseWindows[i];
+
+      mozt.Debug.debug('isHidden: ' + this._windowsHidden);
+      mozt.Debug.debug("bw.visibility: " + bw.visibility);
+      try {
+        if (this._windowsHidden) {
+          bw.visibility = true;
+        } else {
+          bw.visibility = false;
+        }
+      } catch (x) {
+        mozt.Debug.debug(x);
+      }
+      mozt.Debug.debug("bw.visibility: " + bw.visibility);
+
+      mozt.Debug.debug("bw.title: " + bw.title);
+      mozt.Debug.debug("bw.parentNativeWindow: " + bw.parentNativeWindow);
+    }
+
+    if (this._windowsHidden) {
+      this._windowsHidden = false;
+    } else {
+      this._windowsHidden = true;
+    }
+
+  },
+
+  init: function() {            // creates icon
+    try {
+
+      // instanciate tray icon
+      LibGtkStatusIcon.init();
+      this.tray_icon  = LibGtkStatusIcon.gtk_status_icon_new();
+      var mozApp = Services.appinfo.name.toLowerCase();
+      var iconFilename = MOZT_ICON_DIR + mozApp + MOZT_ICON_SUFFIX;
+      LibGtkStatusIcon.gtk_status_icon_set_from_file(this.tray_icon,
+                                                     iconFilename);
+
+      // set tooltip.
+      // TODO: produces:
+      // (firefox-bin:5302): Gdk-CRITICAL **: IA__gdk_window_get_root_coords: assertion `GDK_IS_WINDOW (window)' failed
+      // (thunderbird-bin:5380): Gdk-CRITICAL **: IA__gdk_window_get_root_coords: assertion `GDK_IS_WINDOW (window)' failed
+      LibGtkStatusIcon.gtk_status_icon_set_tooltip_text(this.tray_icon,
+                                                        mozApp);
+
+      // close lib
+      LibGtkStatusIcon.shutdown();
+
+      // watch out for binding problems !
+      mozt_activateCb = LibGObject.GCallback_t(
+        function(){mozt.Handler.showHideToTray();});
+      LibGObject.g_signal_connect(this.tray_icon, "activate",
+                                  mozt_activateCb, null);
+
+    } catch (x) {
+      Components.utils.reportError(x);
+      return false;
+    }
+
+/*
+    try {
+      // Experimental stuff... needs
+      // Components.utils.import("resource://moztray/LibGdkWindow.js");
+
+      var gdkScreen = LibGdkWindow.GdkScreenGetDefault();
+      var tl = LibGdkWindow.GdkScreenGetToplevelWindows(gdkScreen);
+      mozt.Debug.debug(tl);
+
+      // gboolean            gdk_window_is_visible               (GdkWindow *window);
+      mozt_func = LibGObject.GFunc_t(mozt_funcGdkJS);
+      LibGObject.g_list_foreach(tl, mozt_func, null);
+      var gdkWinCount = LibGObject.g_list_length(tl);
+      mozt.Debug.debug('gdkWinCount: ' + gdkWinCount);
+
+      var pid = LibC.getpid();
+      mozt.Debug.debug(pid);
+
+      tl = LibGtkStatusIcon.gtk_window_list_toplevels();
+      mozt_func = LibGObject.GFunc_t(mozt_funcGtkJS);
+      LibGObject.g_list_foreach(tl, mozt_func, null);
+      var gtkWinCount = LibGObject.g_list_length(tl);
+      mozt.Debug.debug('gtkWinCount: ' + gtkWinCount);
+
+    } catch (x) {
+      mozt.Debug.debug(x);
+    }
+*/
+
+    this.initialized = true;
+    return true;
+  },
+
+}; // mozt.Handler
diff --git a/src/modules/commons.js b/src/modules/commons.js
index 68c5412..ce7aca7 100644
--- a/src/modules/commons.js
+++ b/src/modules/commons.js
@@ -1,11 +1,5 @@
 /* -*- Mode: js2; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 
-/*
- * should contain our business logic in JSM, available through service objects,
- * and keep chrome scripts limited to handle presentation logic.
- * http://developer.mozilla.org/en/XUL_School/JavaScript_Object_Management.html
- */
-
 var EXPORTED_SYMBOLS = [ "mozt", "Cc", "Ci", "Cu" ];
 
 const Cc = Components.classes;