Fix the zooming cycle

shell/Shell.py

@@ -84,10 +84,16 @@ class Shell(gobject.GObject):
 
 		self._screen.connect('window-opened', self.__window_opened_cb)
 		self._screen.connect('window-closed', self.__window_closed_cb)
+		self._screen.connect("showing_desktop_changed",
+							 self.__showing_desktop_changed_cb)
 
 	def set_console(self, console):
 		self._console = console
 
+	def __showing_desktop_changed_cb(self, screen):
+		if not screen.get_showing_desktop():
+			self._zoom_level = Shell.ZOOM_ACTIVITY
+
 	def __window_opened_cb(self, screen, window):
 		if window.get_window_type() == wnck.WINDOW_NORMAL:
 			host = ActivityHost(self, window)