[css-scroll-anchoring-1] Add condition to not select scroll anchor when not scrolled from origin

Author: eqrion

css-scroll-anchoring-1/Overview.bs

@@ -19,6 +19,7 @@ Abstract: This spec also proposes an API for web developers to opt-out of this b
 
 <pre class=link-defaults>
 spec:css-box-3; type:dfn; text:content area
+spec:cssom-view-1; type:dfn; text:scrolling area
 spec:css2;
 	type:property;
 		text:max-height
@@ -79,7 +80,9 @@ In some cases, a scrolling box may not select any anchor node.
 	1. If |S| is associated with an element
 		whose computed value of the 'overflow-anchor' property is ''overflow-anchor/none'',
 		then do not select an anchor node for |S|.
-	2. Otherwise, for each DOM child |N| of the element or document associated with |S|,
+	2. If |S| is not scrolled away from the origin of its <a>scrolling area</a> in its
+		<a>block flow direction</a>, then do not select an anchor node for |S|.
+	3. Otherwise, for each DOM child |N| of the element or document associated with |S|,
 		perform the <a>candidate examination algorithm</a> for |N| in |S|,
 		and terminate if it selects an anchor node.
 </div>