From 90d2addc9b8f95f9272f8c2a77bdaf9dfebc0fa8 Mon Sep 17 00:00:00 2001
From: Stephen Blott
Date: Sat, 31 Jan 2015 08:02:46 +0000
Subject: Fix scrolling issue.

On this page:
  - http://www.steephill.tv/dubai-tour/

I was seeing a scrolling problem in my live browser (j/k didn't work
until I clicked on the page), but couldn't reproduce it directly in my
test browser.  That's worrying.

Nevertheless, what was happening was that we succeeded in scrolling a
test amount in one direction, but the scroll to revert failed.  The
consequence was that we concluded (incorrectly) that the element doesn't
scroll.  And j/k scrolling is broken as a result.

How can it be that a scroll in one direction succeeds, but the reverse
does not?

This fixes the problem by not checking whether we are able to undo the
scroll of our test amount.
---
 content_scripts/scroller.coffee | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

(limited to 'content_scripts')

diff --git a/content_scripts/scroller.coffee b/content_scripts/scroller.coffee
index 6e2e1ffc..b9e7d76a 100644
--- a/content_scripts/scroller.coffee
+++ b/content_scripts/scroller.coffee
@@ -75,7 +75,11 @@ doesScroll = (element, direction, amount, factor) ->
   # definitely scrolling backwards, so a delta of -1 will do.  For absolute scrolls, factor is always 1.
   delta = factor * getDimension(element, direction, amount) || -1
   delta = getSign delta # 1 or -1
-  performScroll(element, direction, delta) and performScroll(element, direction, -delta)
+  for change in [ delta, -delta ]
+    if performScroll element, direction, change
+      performScroll element, direction, -change
+      return true
+  false
 
 # From element and its parents, find the first which we should scroll and which does scroll.
 findScrollableElement = (element, direction, amount, factor) ->
-- 
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