optimize refresh

src/textual/messages.py

@@ -34,7 +34,7 @@ class Update(Message, verbosity=3):
 @rich.repr.auto
 class Layout(Message, verbosity=3):
     def can_replace(self, message: Message) -> bool:
-        return isinstance(message, (Layout, Update))
+        return isinstance(message, Layout)
 
 
 @rich.repr.auto

src/textual/screen.py

@@ -174,15 +174,19 @@ class Screen(Widget):
 
     async def handle_update(self, message: messages.Update) -> None:
         message.stop()
+        message.prevent_default()
         widget = message.widget
         assert isinstance(widget, Widget)
         self._dirty_widgets.add(widget)
         self.check_idle()
 
     async def handle_layout(self, message: messages.Layout) -> None:
+        print("LAYOUT")
         message.stop()
+        message.prevent_default()
         self._layout_required = True
         self.check_idle()
+        self._refresh_layout()
 
     def _screen_resized(self, size: Size):
         """Called by App when the screen is resized."""

src/textual/widget.py

@@ -920,11 +920,11 @@ class Widget(DOMNode):
             event (events.Idle): Idle event.
         """
 
-        if self._layout_required:
-            self._layout_required = False
-            self.screen.post_message_no_wait(messages.Layout(self))
-        elif self._repaint_required:
+        if self._repaint_required:
             self.screen.post_message_no_wait(messages.Update(self, self))
+        if self._layout_required:
+            self.screen.post_message_no_wait(messages.Layout(self))
+        self._layout_required = False
         self._repaint_required = False
 
     def focus(self) -> None: