From 3b134d6193c91a493c46363b86458a6e5eace518 Mon Sep 17 00:00:00 2001
From: DanielApt <daniel@knowsis.com>
Date: Mon, 9 Nov 2015 23:11:33 +0000
Subject: [PATCH] Fix broken drag scrolling when left is out of viewport

Related to #390
---
 src/js/plugin/handler/drag-scrollbar.js | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/js/plugin/handler/drag-scrollbar.js b/src/js/plugin/handler/drag-scrollbar.js
index 8fcbe79..5ebe06f 100644
--- a/src/js/plugin/handler/drag-scrollbar.js
+++ b/src/js/plugin/handler/drag-scrollbar.js
@@ -15,7 +15,11 @@ function bindMouseScrollXHandler(element, i) {
 
   function updateScrollLeft(deltaX) {
     var newLeft = currentLeft + (deltaX * i.railXRatio);
-    var maxLeft = i.scrollbarXRail.getBoundingClientRect().left + (i.railXRatio * (i.railXWidth - i.scrollbarXWidth));
+    var scrollbarXLeft = i.scrollbarXRail.getBoundingClientRect().left;
+    if (scrollbarXLeft < 0) {
+      scrollbarXLeft = 0;
+    }
+    var maxLeft = scrollbarXLeft + (i.railXRatio * (i.railXWidth - i.scrollbarXWidth));
 
     if (newLeft < 0) {
       i.scrollbarXLeft = 0;