From 2425ba260f9e53b20cc7c1b8a7c3273af48bef5e Mon Sep 17 00:00:00 2001
From: Darren Burns <darrenb900@gmail.com>
Date: Tue, 10 May 2022 09:55:04 +0100
Subject: [PATCH] Ensure we dont overwrite style object injected into render

---
 sandbox/tabs.py          |  3 ++-
 sandbox/uber.css         |  5 +++++
 src/textual/scrollbar.py | 14 +++++++-------
 3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/sandbox/tabs.py b/sandbox/tabs.py
index db12d8404..efcfcd7c8 100644
--- a/sandbox/tabs.py
+++ b/sandbox/tabs.py
@@ -145,4 +145,5 @@ class BasicApp(App):
             self.mount(example.widget)
 
 
-BasicApp.run(css_path="tabs.scss", watch_css=True, log_path="textual.log")
+app = BasicApp(css_path="tabs.scss", watch_css=True, log_path="textual.log")
+app.run()
diff --git a/sandbox/uber.css b/sandbox/uber.css
index d392f2f65..e0ab19cc2 100644
--- a/sandbox/uber.css
+++ b/sandbox/uber.css
@@ -14,6 +14,11 @@ App.-show-focus *:focus {
   background: darkslateblue;
 }
 
+#child2 {
+  text-style: underline;
+  background: red;
+}
+
 .list-item {
   height: 10;
   color: #12a0;
diff --git a/src/textual/scrollbar.py b/src/textual/scrollbar.py
index 2d8675da5..768720e06 100644
--- a/src/textual/scrollbar.py
+++ b/src/textual/scrollbar.py
@@ -206,17 +206,17 @@ class ScrollBar(Widget):
         yield "position", self.position
 
     def render(self, style: Style) -> RenderableType:
-        style = self.parent.styles
-        style = Style(
+        styles = self.parent.styles
+        scrollbar_style = Style(
             bgcolor=(
-                style.scrollbar_background_hover.rich_color
+                styles.scrollbar_background_hover.rich_color
                 if self.mouse_over
-                else style.scrollbar_background.rich_color
+                else styles.scrollbar_background.rich_color
             ),
             color=(
-                style.scrollbar_color_active.rich_color
+                styles.scrollbar_color_active.rich_color
                 if self.grabbed
-                else style.scrollbar_color.rich_color
+                else styles.scrollbar_color.rich_color
             ),
         )
         return ScrollBarRender(
@@ -224,7 +224,7 @@ class ScrollBar(Widget):
             window_size=self.window_size,
             position=self.position,
             vertical=self.vertical,
-            style=style,
+            style=scrollbar_style,
         )
 
     async def on_event(self, event) -> None: