From af84337437631966a685f86b4d46c5fb393bf473 Mon Sep 17 00:00:00 2001
From: Francis Dominic Fajardo <fofajardo@up.edu.ph>
Date: Fri, 27 Jun 2025 12:23:26 +0800
Subject: [PATCH] Issue #2765 - Follow-up: Make scrollbar width checks use the
 originating non-NAC style context on Linux and Mac

---
 widget/cocoa/nsNativeThemeCocoa.mm | 4 +++-
 widget/gtk/nsNativeThemeGTK.cpp    | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/widget/cocoa/nsNativeThemeCocoa.mm b/widget/cocoa/nsNativeThemeCocoa.mm
index 056c453f2a..5681a40d1d 100644
--- a/widget/cocoa/nsNativeThemeCocoa.mm
+++ b/widget/cocoa/nsNativeThemeCocoa.mm
@@ -2282,7 +2282,9 @@ IsHiDPIContext(nsPresContext* aContext)
 static bool
 IsScrollbarWidthThin(nsIFrame* aFrame)
 {
-  return aFrame->StyleUserInterface()->mScrollbarWidth == StyleScrollbarWidth::Thin;
+  nsStyleContext* styleContext = nsLayoutUtils::GetNonAnonymousStyleContext(aFrame);
+  auto scrollbarWidth = styleContext->StyleUIReset()->mScrollbarWidth;
+  return scrollbarWidth == StyleScrollbarWidth::Thin;
 }
 
 NS_IMETHODIMP
diff --git a/widget/gtk/nsNativeThemeGTK.cpp b/widget/gtk/nsNativeThemeGTK.cpp
index cb4e7debf2..d9fd132d28 100644
--- a/widget/gtk/nsNativeThemeGTK.cpp
+++ b/widget/gtk/nsNativeThemeGTK.cpp
@@ -1101,7 +1101,9 @@ nsNativeThemeGTK::GetExtraSizeForWidget(nsIFrame* aFrame, uint8_t aWidgetType,
 static bool
 IsScrollbarWidthThin(nsIFrame* aFrame)
 {
-  return aFrame->StyleUserInterface()->mScrollbarWidth == StyleScrollbarWidth::Thin;
+  nsStyleContext* styleContext = nsLayoutUtils::GetNonAnonymousStyleContext(aFrame);
+  auto scrollbarWidth = styleContext->StyleUIReset()->mScrollbarWidth;
+  return scrollbarWidth == StyleScrollbarWidth::Thin;
 }
 
 NS_IMETHODIMP