added allow_vertical_scroll and allow_horizontal_scroll

sandbox/will/basic.css

@@ -22,6 +22,8 @@ App > Screen {
   background: $background;
   layout: vertical;
 
+  overflow: hidden;
+  
 }
 
 #tree-container {

sandbox/will/basic.py

@@ -7,7 +7,7 @@ from textual.app import App, ComposeResult
 from textual.reactive import Reactive
 from textual.widget import Widget
 from textual.widgets import Static, DataTable, DirectoryTree, Header, Footer
-from textual.layout import Vertical
+from textual.layout import Container
 
 CODE = '''
 from __future__ import annotations
@@ -120,7 +120,7 @@ class BasicApp(App, css_path="basic.css"):
         table = DataTable()
         self.scroll_to_target = Tweet(TweetBody())
 
-        yield from (
+        yield Container(
             Tweet(TweetBody()),
             Widget(
                 Static(
@@ -141,7 +141,8 @@ class BasicApp(App, css_path="basic.css"):
             Tweet(TweetBody(), classes="scroll-horizontal"),
             Tweet(TweetBody(), classes="scroll-horizontal"),
             Tweet(TweetBody(), classes="scroll-horizontal"),
-            Widget(
+        )
+        yield Widget(
             Widget(classes="title"),
             Widget(classes="user"),
             OptionItem(),
@@ -149,7 +150,6 @@ class BasicApp(App, css_path="basic.css"):
             OptionItem(),
             Widget(classes="content"),
             id="sidebar",
-            ),
         )
         yield Footer()
 

src/textual/widget.py

@@ -135,6 +135,16 @@ class Widget(DOMNode):
     show_vertical_scrollbar = Reactive(False, layout=True)
     show_horizontal_scrollbar = Reactive(False, layout=True)
 
+    @property
+    def allow_vertical_scroll(self) -> bool:
+        """Check if vertical scroll is permitted."""
+        return self.is_scrollable and self.show_vertical_scrollbar
+
+    @property
+    def allow_horizontal_scroll(self) -> bool:
+        """Check if horizontal scroll is permitted."""
+        return self.is_scrollable and self.show_horizontal_scrollbar
+
     def _arrange(self, size: Size) -> DockArrangeResult:
         """Arrange children.
 
@@ -1195,12 +1205,12 @@ class Widget(DOMNode):
                     break
 
     def on_mouse_scroll_down(self, event) -> None:
-        if self.is_scrollable:
+        if self.allow_vertical_scroll:
             if self.scroll_down(animate=False):
                 event.stop()
 
     def on_mouse_scroll_up(self, event) -> None:
-        if self.is_scrollable:
+        if self.allow_vertical_scroll:
             if self.scroll_up(animate=False):
                 event.stop()