diff --git a/browser/base/content/browser.js b/browser/base/content/browser.js
index ed7c3373d53..1fd44abe361 100644
--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -1101,24 +1101,14 @@ function delayedStartup()
   // to create its singleton, whose constructor initializes the service.
   Cc["@mozilla.org/microsummary/service;1"].getService(Ci.nsIMicrosummaryService);
 
-  // initialize the session-restore service
-  var ssEnabled = true;
-  var prefBranch = Cc["@mozilla.org/preferences-service;1"].
-                   getService(Ci.nsIPrefBranch);
-  try {
-    ssEnabled = prefBranch.getBoolPref("browser.sessionstore.enabled");
-  } catch (ex) {}
-
-  if (ssEnabled) {
-    var wType = window.document.documentElement.getAttribute("windowtype");
-    if (wType == "navigator:browser") {
-      try {
-        var ss = Cc["@mozilla.org/browser/sessionstore;1"].
-                 getService(Ci.nsISessionStore);
-        ss.init(window);
-      } catch(ex) {
-        dump("nsSessionStore could not be initialized: " + ex + "\n");
-      }
+  // initialize the session-restore service (in case it's not already running)
+  if (document.documentElement.getAttribute("windowtype") == "navigator:browser") {
+    try {
+      var ss = Cc["@mozilla.org/browser/sessionstore;1"].
+               getService(Ci.nsISessionStore);
+      ss.init(window);
+    } catch(ex) {
+      dump("nsSessionStore could not be initialized: " + ex + "\n");
     }
   }
 
diff --git a/browser/components/sessionstore/src/nsSessionStartup.js b/browser/components/sessionstore/src/nsSessionStartup.js
index 82d04297866..7fa93642878 100644
--- a/browser/components/sessionstore/src/nsSessionStartup.js
+++ b/browser/components/sessionstore/src/nsSessionStartup.js
@@ -121,9 +121,6 @@ SessionStartup.prototype = {
     if (!this._getPref("sessionstore.enabled", DEFAULT_ENABLED))
       return;
 
-    var observerService = Cc["@mozilla.org/observer-service;1"].
-                          getService(Ci.nsIObserverService);
-    
     // get file references
     var dirService = Cc["@mozilla.org/file/directory_service;1"].
                      getService(Ci.nsIProperties);
@@ -166,6 +163,13 @@ SessionStartup.prototype = {
     if (this._getPref("sessionstore.resume_session_once", DEFAULT_RESUME_SESSION_ONCE)) {
       this._prefBranch.setBoolPref("sessionstore.resume_session_once", false);
     }
+    
+    if (this.doRestore()) {
+      // wait for the first browser window to open
+      var observerService = Cc["@mozilla.org/observer-service;1"].
+                            getService(Ci.nsIObserverService);
+      observerService.addObserver(this, "domwindowopened", true);
+    }
   },
 
   /**
@@ -186,9 +190,37 @@ SessionStartup.prototype = {
       observerService.removeObserver(this, "final-ui-startup");
       this.init();
       break;
+    case "domwindowopened":
+      var window = aSubject;
+      var self = this;
+      window.addEventListener("load", function() {
+        self._onWindowOpened(window);
+        window.removeEventListener("load", arguments.callee, false);
+      }, false);
+      break;
     }
   },
 
+  /**
+   * Removes the default arguments from the first browser window
+   * (and removes the "domwindowopened" observer afterwards)
+   */
+  _onWindowOpened: function sss_onWindowOpened(aWindow) {
+    var wType = aWindow.document.documentElement.getAttribute("windowtype");
+    if (wType != "navigator:browser")
+      return;
+    
+    var defaultArgs = Cc["@mozilla.org/browser/clh;1"].
+                      getService(Ci.nsIBrowserHandler).defaultArgs;
+    if (aWindow.arguments && aWindow.arguments[0] &&
+        aWindow.arguments[0] == defaultArgs)
+      aWindow.arguments[0] = null;
+    
+    var observerService = Cc["@mozilla.org/observer-service;1"].
+                          getService(Ci.nsIObserverService);
+    observerService.removeObserver(this, "domwindowopened");
+  },
+
 /* ........ Public API ................*/
 
   /**
diff --git a/browser/components/sessionstore/src/nsSessionStore.js b/browser/components/sessionstore/src/nsSessionStore.js
index b717941696d..4679d026c47 100644
--- a/browser/components/sessionstore/src/nsSessionStore.js
+++ b/browser/components/sessionstore/src/nsSessionStore.js
@@ -172,10 +172,7 @@ SessionStoreService.prototype = {
    * Initialize the component
    */
   init: function sss_init(aWindow) {
-    if (!aWindow || aWindow == null)
-      return;
-
-    if (this._loadState == STATE_RUNNING)
+    if (!aWindow || this._loadState == STATE_RUNNING)
       return;
 
     this._prefBranch = Cc["@mozilla.org/preferences-service;1"].
@@ -246,10 +243,7 @@ SessionStoreService.prototype = {
     }
 
     // As this is called at delayedStartup, restoration must be initiated here
-    var windowLoad = function(self) {
-      self.onLoad(this);
-    }
-    aWindow.setTimeout(windowLoad, 0, this);
+    this.onLoad(aWindow);
   },
 
   /**
@@ -274,9 +268,6 @@ SessionStoreService.prototype = {
    * Handle notifications
    */
   observe: function sss_observe(aSubject, aTopic, aData) {
-    var observerService = Cc["@mozilla.org/observer-service;1"].
-                          getService(Ci.nsIObserverService);
-
     // for event listeners
     var _this = this;
 
@@ -1822,38 +1813,13 @@ SessionStoreService.prototype = {
    * @returns bool
    */
   _isCmdLineEmpty: function sss_isCmdLineEmpty(aWindow) {
-    if (!aWindow.arguments) {
-      return true;
-    }
-    
-    var homepage = null;
-    switch (this._getPref("startup.page", 1)) {
-    case 0:
-    case 3:
-      homepage = "about:blank";
-      break;
-    case 1:
-      try {
-        homepage = this._prefBranch.getComplexValue("startup.homepage", Ci.nsIPrefLocalizedString).data;
-      }
-      catch (ex) {
-        homepage = this._getPref("startup.homepage", "");
-      }
-      break;
-    case 2:
-      homepage = Cc["@mozilla.org/browser/global-history;2"].
-                 getService(Ci.nsIBrowserHistory).lastPageVisited;
-      break;
-    }
-    
-    for (var i = 0; i < aWindow.arguments.length; i++) {
-      var url = aWindow.arguments[i].split("\n")[0];
-      if (!url || url == homepage) {
-        aWindow.arguments.splice(i--, 1);
-      }
-    }
-    
-    return (aWindow.arguments.length == 0);
+    var defaultArgs = Cc["@mozilla.org/browser/clh;1"].
+                      getService(Ci.nsIBrowserHandler).defaultArgs;
+    if (aWindow.arguments && aWindow.arguments[0] &&
+        aWindow.arguments[0] == defaultArgs)
+      aWindow.arguments[0] = null;
+
+    return !aWindow.arguments || !aWindow.arguments[0];
   },
 
   /**