diff --git a/examples/calculator.py b/examples/calculator.py
index 9770228c1..8fc80f40a 100644
--- a/examples/calculator.py
+++ b/examples/calculator.py
@@ -208,7 +208,7 @@ class Calculator(GridView):
 class CalculatorApp(App):
     """The Calculator Application"""
 
-    async def on_mount(self, event: events.Mount) -> None:
+    async def on_mount(self) -> None:
         """Mount the calculator widget."""
         await self.view.dock(Calculator())
 
diff --git a/src/textual/geometry.py b/src/textual/geometry.py
index f057f998b..a10f52635 100644
--- a/src/textual/geometry.py
+++ b/src/textual/geometry.py
@@ -92,6 +92,16 @@ class Size(NamedTuple):
         width, height = self
         return Region(0, 0, width, height)
 
+    def __add__(self, other: tuple[int, int]) -> Size:
+        width, height = self
+        width2, height2 = other
+        return Size(width + width2, height + height2)
+
+    def __sub__(self, other: tuple[int, int]) -> Size:
+        width, height = self
+        width2, height2 = other
+        return Size(width - width2, height - height2)
+
     def contains(self, x: int, y: int) -> bool:
         """Check if a point is in the size.
 
diff --git a/src/textual/layout.py b/src/textual/layout.py
index 3b3b1de4f..dfba4b4e0 100644
--- a/src/textual/layout.py
+++ b/src/textual/layout.py
@@ -263,7 +263,7 @@ class Layout(ABC):
 
             lines = widget._get_lines()
 
-            if clip in region:
+            if region in clip:
                 yield region, clip, lines
             elif clip.overlaps(region):
                 new_region = region.intersection(clip)
diff --git a/src/textual/layouts/vertical.py b/src/textual/layouts/vertical.py
index c128d7e55..63eccc3ae 100644
--- a/src/textual/layouts/vertical.py
+++ b/src/textual/layouts/vertical.py
@@ -3,6 +3,7 @@ from __future__ import annotations
 from typing import Iterable
 
 from rich.console import Console
+from rich.measure import Measurement
 
 from .. import log
 from ..geometry import Offset, Region, Size
@@ -34,6 +35,9 @@ class VerticalLayout(Layout):
         width, height = size
         gutter_height, gutter_width = self.gutter
         render_width = width - gutter_width * 2
+
+        render_width = 1000 + gutter_width * 2
+
         x = gutter_width
         y = gutter_height
         map: LayoutMap = LayoutMap(size)
diff --git a/src/textual/widgets/_scroll_view.py b/src/textual/widgets/_scroll_view.py
index 4a187e127..74338d57e 100644
--- a/src/textual/widgets/_scroll_view.py
+++ b/src/textual/widgets/_scroll_view.py
@@ -126,7 +126,7 @@ class ScrollView(View):
 
     def scroll_to_center(self, line: int) -> None:
         self.target_y = line - self.size.height // 2
-        if abs(self.target_y - self.y) > 2:
+        if abs(self.target_y - self.y) > 1:
             # Animate if its more than 1
             self.animate("y", self.target_y, easing="out_cubic")
         else:
@@ -190,18 +190,24 @@ class ScrollView(View):
         self.animate("x", self.target_x, speed=150, easing="out_cubic")
         self.animate("y", self.target_y, speed=150, easing="out_cubic")
 
-    async def handle_window_change(self, message: Message) -> None:
-        virtual_size = self.window.virtual_size
+    def handle_window_change(self) -> None:
+        virtual_width, virtual_height = self.virtual_size
+        width, height = self.size
+
+        self.log(self.virtual_size, self.size)
         self.x = self.validate_x(self.x)
         self.y = self.validate_y(self.y)
-        self.vscroll.virtual_size = virtual_size.height
-        self.vscroll.window_size = self.size.height
+
+        self.hscroll.virtual_size = virtual_width
+        self.hscroll.window_size = width
+        self.vscroll.virtual_size = virtual_height
+        self.vscroll.window_size = height
 
         assert isinstance(self.layout, GridLayout)
 
-        if self.layout.show_column("vscroll", virtual_size.height > self.size.height):
+        if self.layout.show_column("vscroll", virtual_height > height):
             self.refresh()
-        if self.layout.show_row("hscroll", virtual_size.width > self.size.width):
+        if self.layout.show_row("hscroll", virtual_width > width):
             self.refresh()
 
     def handle_cursor_move(self, message: CursorMove) -> None: