refactor of compositor

sandbox/uber.py

@@ -1,3 +1,4 @@
+from tkinter import Place
 from textual.app import App
 from textual import events
 from textual.widgets import Placeholder
@@ -9,7 +10,22 @@ class BasicApp(App):
 
     def on_mount(self):
         """Build layout here."""
-        self.mount(uber=Placeholder())
+
+        uber2 = Widget()
+        uber2.add_children(
+            Placeholder(id="uber2-child1"),
+            Placeholder(id="uber2-child2"),
+        )
+
+        self.mount(
+            uber=Widget(
+                Placeholder(id="child1"),
+                Placeholder(id="child2"),
+                Placeholder(id="child3"),
+            ),
+            uber2=uber2,
+        )
+        # self.panic(self.tree)
 
     async def on_key(self, event: events.Key) -> None:
         await self.dispatch_key(event)