diff --git a/shell/view/Shell.py b/shell/view/Shell.py
index f95cf313..9eb8d469 100644
--- a/shell/view/Shell.py
+++ b/shell/view/Shell.py
@@ -81,10 +81,7 @@ class Shell(gobject.GObject):
 	def __active_window_changed_cb(self, screen):
 		window = screen.get_active_window()
 
-		if window == None:
-			self._model.set_current_activity(None)
-			self.emit('activity-changed', None)
-		elif window.get_window_type() == wnck.WINDOW_NORMAL:
+		if window and window.get_window_type() == wnck.WINDOW_NORMAL:
 			activity_host = self._hosts[window.get_xid()]
 
 			current = self._model.get_current_activity()
@@ -101,6 +98,10 @@ class Shell(gobject.GObject):
 				self.emit('activity-closed', host)
 				del self._hosts[window.get_xid()]
 
+		if len(self._hosts) == 0:
+			self._model.set_current_activity(None)
+			self.emit('activity-changed', None)
+
 	def get_model(self):
 		return self._model