diff --git a/examples/code_browser.css b/examples/code_browser.css
new file mode 100644
index 000000000..f2b476035
--- /dev/null
+++ b/examples/code_browser.css
@@ -0,0 +1,26 @@
+#tree-view {
+    display: none;
+    scrollbar-gutter: stable;
+}
+
+CodeBrowser.-show-tree #tree-view {
+    display: block;
+    dock: left;
+    height: 100%;
+    width: auto;
+    background: $surface; 
+    
+}
+
+CodeBrowser{
+    background: $surface-darken-1;    
+}
+
+DirectoryTree {
+    padding-right: 1;
+   
+}
+
+#code {
+    width: auto;
+}
diff --git a/examples/code_browser.py b/examples/code_browser.py
new file mode 100644
index 000000000..93e06056d
--- /dev/null
+++ b/examples/code_browser.py
@@ -0,0 +1,49 @@
+import sys
+
+from rich.syntax import Syntax
+from rich.traceback import Traceback
+from textual.app import App, ComposeResult
+from textual.layout import Container, Vertical
+from textual.reactive import Reactive
+from textual.widgets import DirectoryTree, Footer, Header, Static
+
+
+class CodeBrowser(App):
+
+    show_tree = Reactive.init(True)
+
+    def watch_show_tree(self, show_tree: bool) -> None:
+        self.set_class(show_tree, "-show-tree")
+
+    def on_load(self) -> None:
+        self.bind("t", "toggle_tree", description="Toggle Tree")
+        self.bind("q", "quit", description="Quit")
+
+    def compose(self) -> ComposeResult:
+        path = "./" if len(sys.argv) < 2 else sys.argv[1]
+        yield Header()
+        yield Container(
+            Vertical(DirectoryTree(path), id="tree-view"),
+            Vertical(Static(id="code"), id="code-view"),
+        )
+        yield Footer()
+
+    def on_directory_tree_file_click(self, event: DirectoryTree.FileClick) -> None:
+        code_view = self.query_one("#code", Static)
+        try:
+            syntax = Syntax.from_path(event.path, line_numbers=True, word_wrap=True)
+        except Exception:
+            code_view.update(Traceback())
+            self.sub_title = "ERROR"
+        else:
+            code_view.update(syntax)
+            self.query_one("#code-view").scroll_home(animate=False)
+            self.sub_title = event.path
+
+    def action_toggle_tree(self) -> None:
+        self.show_tree = not self.show_tree
+
+
+app = CodeBrowser(css_path="code_browser.css")
+if __name__ == "__main__":
+    app.run()
diff --git a/src/textual/_layout.py b/src/textual/_layout.py
index a59ded61e..49284bddb 100644
--- a/src/textual/_layout.py
+++ b/src/textual/_layout.py
@@ -65,9 +65,14 @@ class Layout(ABC):
             int: Width of the content.
         """
         width: int | None = None
+        widget_gutter = widget.gutter.width
         for child in widget.displayed_children:
             if not child.is_container:
-                child_width = child.get_content_width(container, viewport)
+                child_width = (
+                    child.get_content_width(container, viewport)
+                    + widget_gutter
+                    + child.gutter.width
+                )
                 width = child_width if width is None else max(width, child_width)
         if width is None:
             width = container.width
diff --git a/src/textual/dom.py b/src/textual/dom.py
index 70bc64924..e21b440a9 100644
--- a/src/textual/dom.py
+++ b/src/textual/dom.py
@@ -544,7 +544,7 @@ class DOMNode(MessagePump):
         return nodes
 
     @property
-    def displayed_children(self) -> list[DOMNode]:
+    def displayed_children(self) -> list[Widget]:
         """The children which don't have display: none set.
 
         Returns:
diff --git a/src/textual/layout.py b/src/textual/layout.py
index b06c347c3..ae22aaaf5 100644
--- a/src/textual/layout.py
+++ b/src/textual/layout.py
@@ -8,6 +8,7 @@ class Container(Widget):
     Container {
         layout: vertical;       
         overflow: auto;
+      
     }    
     """
 
diff --git a/src/textual/widget.py b/src/textual/widget.py
index 65b847d23..ea0140b7f 100644
--- a/src/textual/widget.py
+++ b/src/textual/widget.py
@@ -7,8 +7,13 @@ from operator import attrgetter
 from typing import TYPE_CHECKING, ClassVar, Collection, Iterable, NamedTuple
 
 import rich.repr
-from rich.console import Console, JustifyMethod, RenderableType
-from rich.measure import Measurement
+from rich.console import (
+    Console,
+    ConsoleRenderable,
+    Measurement,
+    JustifyMethod,
+    RenderableType,
+)
 from rich.segment import Segment
 from rich.style import Style
 from rich.styled import Styled
@@ -313,17 +318,15 @@ class Widget(DOMNode):
         """
         if self.is_container:
             assert self._layout is not None
-            return (
-                self._layout.get_content_width(self, container, viewport)
-                + self.scrollbar_size_vertical
-            )
+            return self._layout.get_content_width(self, container, viewport)
 
         cache_key = container.width
         if self._content_width_cache[0] == cache_key:
             return self._content_width_cache[1]
 
         console = self.app.console
-        renderable = self.render()
+        renderable = self.post_render(self.render())
+
         measurement = Measurement.get(
             console,
             console.options.update_width(container.width),
@@ -509,18 +512,18 @@ class Widget(DOMNode):
     @property
     def scrollbar_size_vertical(self) -> int:
         """Get the width used by the *vertical* scrollbar."""
-        return (
-            self.styles.scrollbar_size_vertical if self.show_vertical_scrollbar else 0
-        )
+        styles = self.styles
+        if styles.scrollbar_gutter == "stable" and styles.overflow_y == "auto":
+            return styles.scrollbar_size_vertical
+        return styles.scrollbar_size_vertical if self.show_vertical_scrollbar else 0
 
     @property
     def scrollbar_size_horizontal(self) -> int:
         """Get the height used by the *horizontal* scrollbar."""
-        return (
-            self.styles.scrollbar_size_horizontal
-            if self.show_horizontal_scrollbar
-            else 0
-        )
+        styles = self.styles
+        if styles.scrollbar_gutter == "stable" and styles.overflow_x == "auto":
+            return self.styles.scrollbar_size_horizontal
+        return styles.scrollbar_size_horizontal if self.show_horizontal_scrollbar else 0
 
     @property
     def scrollbar_gutter(self) -> Spacing:
@@ -1214,7 +1217,7 @@ class Widget(DOMNode):
         if self.descendant_has_focus:
             yield "focus-within"
 
-    def post_render(self, renderable: RenderableType) -> RenderableType:
+    def post_render(self, renderable: RenderableType) -> ConsoleRenderable:
         """Applies style attributes to the default renderable.
 
         Returns:
diff --git a/src/textual/widgets/_directory_tree.py b/src/textual/widgets/_directory_tree.py
index d718888de..9512641f1 100644
--- a/src/textual/widgets/_directory_tree.py
+++ b/src/textual/widgets/_directory_tree.py
@@ -21,14 +21,13 @@ class DirEntry:
     is_dir: bool
 
 
-@rich.repr.auto
-class FileClick(Message, bubble=True):
-    def __init__(self, sender: MessageTarget, path: str) -> None:
-        self.path = path
-        super().__init__(sender)
-
-
 class DirectoryTree(TreeControl[DirEntry]):
+    @rich.repr.auto
+    class FileClick(Message, bubble=True):
+        def __init__(self, sender: MessageTarget, path: str) -> None:
+            self.path = path
+            super().__init__(sender)
+
     def __init__(
         self,
         path: str,
@@ -112,7 +111,7 @@ class DirectoryTree(TreeControl[DirEntry]):
     ) -> None:
         dir_entry = message.node.data
         if not dir_entry.is_dir:
-            await self.emit(FileClick(self, dir_entry.path))
+            await self.emit(self.FileClick(self, dir_entry.path))
         else:
             if not message.node.loaded:
                 await self.load_directory(message.node)
diff --git a/src/textual/widgets/_header.py b/src/textual/widgets/_header.py
index 26cb4bea0..515c5e2c3 100644
--- a/src/textual/widgets/_header.py
+++ b/src/textual/widgets/_header.py
@@ -63,7 +63,8 @@ class HeaderTitle(Widget):
     def render(self) -> Text:
         text = Text(self.text, no_wrap=True, overflow="ellipsis")
         if self.sub_text:
-            text.append(f" - {self.sub_text}", "dim")
+            text.append(" — ")
+            text.append(self.sub_text, "dim")
         return text
 
 
@@ -83,8 +84,13 @@ class Header(Widget):
     }
     """
 
+    tall = Reactive(True)
+
     DEFAULT_CLASSES = "tall"
 
+    def watch_tall(self, tall: bool) -> None:
+        self.set_class(tall, "tall")
+
     async def on_click(self, event):
         self.toggle_class("tall")
 
diff --git a/src/textual/widgets/_static.py b/src/textual/widgets/_static.py
index 824248ce7..5e5c74a64 100644
--- a/src/textual/widgets/_static.py
+++ b/src/textual/widgets/_static.py
@@ -1,9 +1,9 @@
 from __future__ import annotations
 
 from rich.console import RenderableType
-
 from rich.protocol import is_renderable
 
+from ..reactive import Reactive
 from ..errors import RenderError
 from ..widget import Widget
 
@@ -49,4 +49,4 @@ class Static(Widget):
     def update(self, renderable: RenderableType) -> None:
         _check_renderable(renderable)
         self.renderable = renderable
-        self.refresh()
+        self.refresh(layout=True)
diff --git a/src/textual/widgets/_tree_control.py b/src/textual/widgets/_tree_control.py
index 05f8f5b13..51c05a92c 100644
--- a/src/textual/widgets/_tree_control.py
+++ b/src/textual/widgets/_tree_control.py
@@ -13,7 +13,7 @@ from ..geometry import Region, Size
 from .. import events
 from ..reactive import Reactive
 from .._types import MessageTarget
-from ..widget import Widget
+from ..widgets import Static
 from ..message import Message
 from .. import messages
 
@@ -161,7 +161,7 @@ class TreeNode(Generic[NodeDataType]):
         return self._control.render_node(self)
 
 
-class TreeControl(Generic[NodeDataType], Widget, can_focus=True):
+class TreeControl(Generic[NodeDataType], Static, can_focus=True):
     DEFAULT_CSS = """
     TreeControl {
         background: $surface;