From 0bb2be7a27744617abd4aaff0a3640c5a133ddc8 Mon Sep 17 00:00:00 2001
From: David Awogbemila <awogbemila@chromium.org>
Date: Fri, 20 Sep 2024 11:57:58 -0400
Subject: [PATCH] Resolve multiple scroll-start-targets by reverse DOM order

---
 css-scroll-snap-2/Overview.bs | 54 +++++++++++++++++------------------
 1 file changed, 27 insertions(+), 27 deletions(-)

diff --git a/css-scroll-snap-2/Overview.bs b/css-scroll-snap-2/Overview.bs
index 0b004832b23..0214ab57698 100644
--- a/css-scroll-snap-2/Overview.bs
+++ b/css-scroll-snap-2/Overview.bs
@@ -137,31 +137,32 @@ The 'scroll-start-target' property {#scroll-start-target}
 <h4 dfn export id="initial-scroll-target">
 Initial scroll target</h4>
 
-	The [=initial scroll target=] of a <a>scroll container</a> |scrollcontainer|
+	An [=initial scroll target=] of a <a>scroll container</a> |scrollcontainer|
 	is an element or pseudo-element
 	whose 'scroll-start-target'property is non-''scroll-start-target/none''
-	and whose nearest <a>scroll container</a> is |scrollcontainer|.
-	When multiple such elements or pseudo-elements exist,
-	user-agents should select the one
-	which comes first in [=tree order=].
-	When no such element or pseudo-element exists,
-	|scrollcontainer|’s <a>initial scroll target</a> is null.
-
-	<div algorithm="determine the initial scroll position from an initial scroll target">
-		If the <a>initial scroll target</a> of a <a>scroll container</a> is not null,
-		it  should be used to determine the <a>initial scroll position</a> of |scrollcontainer|
-		by running the following steps:
-
-		1. Let |target| be the <a>initial scroll target</a> for |scrollcontainer|.
-		1. Let |position| be the result of running the steps to
-			<a spec="cssom-view-1">determine the scroll-into-view position</a> of |target|
-			with <var ignore>behavior</var> set to "auto",
-			<var ignore>block</var> set to "start",
-			<var ignore>inline</var> set to "nearest",
-			and <var ignore>scrolling box</var> set to |scrollcontainer|.
-		1. Set |scrollcontainer|'s <a>initial scroll position</a> to |position|.
-	</div>
-
+	and whose nearest <a>scroll container</a> is |scrollcontainer|. |scrollcontainer|
+	may have more than one <a>initial scroll target</a>.
+
+	<h5 dfn id="determine-scroll-start-target-position">Determining initial scroll position from
+	scroll-start-target</h5>
+	To determine the <a>initial scroll position</a> of a <a>scroll container</a> |scrollcontainer| using its
+	<a>initial scroll target</a>s, user-agents should run the following steps:
+
+		1. Let <dfn>initial-scroll-target-list</dfn> be a list of the <a>initial scroll target</a>s of |scrollcontainer|,
+			sorted in reverse <a data-link-type="dfn" href="https://dom.spec.whatwg.org/#concept-tree-order" id="ref-for-concept-tree-order">tree order</a>.
+		1. For |target| in <a>initial-scroll-target-list</a>:
+			1.  Let |position| be the result of running the steps to
+				<a spec="cssom-view-1">determine the scroll-into-view position</a> of |target|
+				with <var ignore>behavior</var> set to "auto",
+				<var ignore>block</var> set to "start",
+				<var ignore>inline</var> set to "nearest",
+				and <var ignore>scrolling box</var> set to |scrollcontainer|.
+			1. Set |scrollcontainer|'s <a>initial scroll position</a> to |position|.
+
+NOTE: Sorting <a>initial-scroll-target-list</a> in reverse
+<a data-link-type="dfn" href="https://dom.spec.whatwg.org/#concept-tree-order" id="ref-for-concept-tree-order">tree order</a>
+is intended to prioritize having the first <a>initial scroll target</a> in tree order
+scrolled into view.
 
 <h4 id="scroll-start-target-propdef">scroll-start-target Property Definition</h4>
 
@@ -199,10 +200,9 @@ Post-first layout arrivals</h4>
 	a <a>scroll container's</a> [=initial scroll target=] might arrive
 	after that <a>scroll container</a> has been laid out.
 	If this happens,
-	user agents should still scroll to the [=initial scroll target=]
-	unless the user agent has reason to believe
-	the user is no longer interested
-	in scrolling to the <a>initial scroll position</a>.
+	user agents should still scroll to the <a>initial scroll position</a>
+	<a href="determine-scroll-start-target-position">determined</a> by 'scroll-start-target' unless the user agent has reason to believe
+	the user is no longer interested in scrolling to the <a>initial scroll position</a>.
 
 
 <!-- Big Text: :snapped