Adding data_change to use to signal to Screenful that save button nedds a litle star

src/message/message.py

@@ -25,6 +25,9 @@ class Message:
         
         return result
     
+    def data_change(self):
+        return True
+    
     def add_arg(self, arg):
         self._args.append(arg)
     
@@ -35,6 +38,9 @@ class Message:
 class ClickMessage(Message):
     def on_event(self, event):
         event.stopPropagation()
+    
+    def data_change(self):
+        return False
         
 
 def msg(message, params):