From ac2e1077107d72ef82e1424634aa86945696e6b4 Mon Sep 17 00:00:00 2001
From: Stephen Blott
Date: Fri, 19 Dec 2014 08:35:03 +0000
Subject: Initialize scroller to *largest* visible scrollable element.

---
 content_scripts/scroller.coffee | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

(limited to 'content_scripts')

diff --git a/content_scripts/scroller.coffee b/content_scripts/scroller.coffee
index 48b99cff..dec817a1 100644
--- a/content_scripts/scroller.coffee
+++ b/content_scripts/scroller.coffee
@@ -84,14 +84,17 @@ findScrollableElement = (element, direction, amount, factor) ->
       element = element.parentElement || document.body
   element
 
-# On some pages, document.body is not scrollable.  Here, we search the document for the first visible element
-# which does scroll vertically. This is used to initialize activatedElement. See #1358.
+# On some pages, document.body is not scrollable.  Here, we search the document for the largest visible
+# element which does scroll vertically. This is used to initialize activatedElement. See #1358.
 firstScrollableElement = (element=document.body) ->
   if doesScroll element, "y", 1, 1
     element
   else
-    for child in element.children
-      return ele if DomUtils.getVisibleClientRect(child) and ele = firstScrollableElement child
+    children = ({element: child, rect: DomUtils.getVisibleClientRect(child)} for child in element.children)
+    children = children.filter (child) -> child.rect # Filter out non-visible elements.
+    children.map (child) -> child.area = child.rect.width * child.rect.height
+    for child in children.sort((a,b) -> b.area - a.area) # Largest to smallest by visible area.
+      return ele if ele = firstScrollableElement child.element
     null
 
 checkVisibility = (element) ->
-- 
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