Update layout.py

I put enable/disable method for GUI pieces instead of disconnecting event. So I want to know if the `set_event` is necessary (this method can choose the GUI piece that we want to disable. Is it necessary or we will just block all GUI piece ?). 
Morever, I would like to know if there is a possibility to lock Cue instead of locking Widget because with this method all cues are affected (if we want to add a Preparation Mode which will affect only not running cues)

lisp/plugins/list_layout/layout.py

@@ -348,13 +348,9 @@ def _set_selection_mode(self, enable):
     def _set_live_mode(self, enable):
         self.live_mode_action.setChecked(enable)
         if enable:
-            for event in ListLayout.event_list:
-                if event.get("live_mode") == True:
-                    event.get("element").disconnect()
+            self._view.setEnabled(False)
         else:
-            for event in ListLayout.event_list:
-                if event.get("live_mode") == True:
-                    event.get("element").connect(event.get("action"))
+            self._view.setEnabled(True)
 
     @live_mode.get
     def _get_live_mode(self):