diff --git a/shell/model/homemodel.py b/shell/model/homemodel.py
index 5f985718..f4fd3eec 100644
--- a/shell/model/homemodel.py
+++ b/shell/model/homemodel.py
@@ -70,7 +70,10 @@ class HomeModel(gobject.GObject):
 
     def _active_window_changed_cb(self, screen):
         window = screen.get_active_window()
-        if not window or window.get_window_type() != wnck.WINDOW_NORMAL:
+        if window == None:
+            self.emit('active-activity-changed', None)
+            return
+        if window.get_window_type() != wnck.WINDOW_NORMAL:
             return
 
         xid = window.get_xid()
diff --git a/shell/view/Shell.py b/shell/view/Shell.py
index c4b4b1e4..5bce1074 100644
--- a/shell/view/Shell.py
+++ b/shell/view/Shell.py
@@ -142,7 +142,10 @@ class Shell(gobject.GObject):
             del self._hosts[xid]
 
     def _active_activity_changed_cb(self, home_model, home_activity):
-        host = self._hosts[home_activity.get_xid()]
+        if home_activity:
+            host = self._hosts[home_activity.get_xid()]
+        else:
+            host = None
 
         if self._current_host:
             self._current_host.set_active(False)