diff --git a/docs/examples/introduction/intro02.py b/docs/examples/introduction/intro02.py
index 2f5d3ed64..cde514be6 100644
--- a/docs/examples/introduction/intro02.py
+++ b/docs/examples/introduction/intro02.py
@@ -3,6 +3,10 @@ from textual.app import App
 
 class ExampleApp(App):
 
+    CSS = """
+
+    """
+
     COLORS = [
         "white",
         "maroon",
@@ -18,12 +22,15 @@ class ExampleApp(App):
 
     def on_mount(self):
         self.styles.background = "darkblue"
+        self.bind("t", "tree")
 
     def on_key(self, event):
         if event.key.isdigit():
             self.styles.background = self.COLORS[int(event.key)]
         self.bell()
 
+    def action_tree(self):
+        self.log(self.tree)
 
 app = ExampleApp()
 app.run()
diff --git a/src/textual/_compositor.py b/src/textual/_compositor.py
index ba2f30f29..6b6848c5f 100644
--- a/src/textual/_compositor.py
+++ b/src/textual/_compositor.py
@@ -498,7 +498,7 @@ class Compositor:
         """Get rendered widgets (lists of segments) in the composition.
 
         Returns:
-            Iterable[tuple[Region, Region, Lines]]: An interable of <region>, <clip region>, and <lines>
+            Iterable[tuple[Region, Region, Lines]]: An iterable of <region>, <clip region>, and <lines>
         """
         # If a renderable throws an error while rendering, the user likely doesn't care about the traceback
         # up to this point.
diff --git a/src/textual/app.py b/src/textual/app.py
index 366d733f0..88db0ec06 100644
--- a/src/textual/app.py
+++ b/src/textual/app.py
@@ -526,7 +526,7 @@ class App(Generic[ReturnType], DOMNode):
                 self.screen.refresh(layout=True)
 
     def render(self) -> RenderableType:
-        return ""
+        return Blank("red")
 
     def query(self, selector: str | None = None) -> DOMQuery:
         """Get a DOM query in the current screen.
@@ -999,7 +999,6 @@ class App(Generic[ReturnType], DOMNode):
             action_target = default_namespace or self
             action_name = target
 
-        log("<action>", action)
         await self.dispatch_action(action_target, action_name, params)
 
     async def dispatch_action(
@@ -1014,6 +1013,8 @@ class App(Generic[ReturnType], DOMNode):
         _rich_traceback_guard = True
         method_name = f"action_{action_name}"
         method = getattr(namespace, method_name, None)
+        if method is None:
+            log(f"<action> {action_name!r} has no target")
         if callable(method):
             await invoke(method, *params)
 
diff --git a/src/textual/css/styles.py b/src/textual/css/styles.py
index ae3e7f5a1..7a079fb3b 100644
--- a/src/textual/css/styles.py
+++ b/src/textual/css/styles.py
@@ -476,6 +476,7 @@ class Styles(StylesBase):
         return self._rules.get(rule, default)
 
     def refresh(self, *, layout: bool = False) -> None:
+        print(self, self.node, "REFRESH", layout)
         if self.node is not None:
             self.node.refresh(layout=layout)
 
diff --git a/src/textual/renderables/blank.py b/src/textual/renderables/blank.py
index a0df77ed1..9dd07b7d9 100644
--- a/src/textual/renderables/blank.py
+++ b/src/textual/renderables/blank.py
@@ -24,7 +24,7 @@ class Blank:
         width = options.max_width
         height = options.height or options.max_height
 
-        segment = Segment(f"{' ' * width}", style=self._style)
+        segment = Segment(" " * width, self._style)
         line = Segment.line()
         for _ in range(height):
             yield segment
diff --git a/src/textual/screen.py b/src/textual/screen.py
index 12b8565e8..b24a6405e 100644
--- a/src/textual/screen.py
+++ b/src/textual/screen.py
@@ -31,8 +31,10 @@ class Screen(Widget):
     Screen {
         layout: vertical;
         overflow-y: auto;
+        /*
         background: $surface;
         color: $text-surface;
+        */
     }
     """