From b729db39135bd95d06e6f0826357c0174bd04bcf Mon Sep 17 00:00:00 2001
From: Vincent Vanwaelscappel <vincent@cubedesigners.com>
Date: Mon, 2 Oct 2017 17:47:17 +0200
Subject: [PATCH] fix #1692 @0.25

---
 js/libs/fluidbook/fluidbook.slider.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/js/libs/fluidbook/fluidbook.slider.js b/js/libs/fluidbook/fluidbook.slider.js
index 18decfc1..3cc3597e 100644
--- a/js/libs/fluidbook/fluidbook.slider.js
+++ b/js/libs/fluidbook/fluidbook.slider.js
@@ -65,7 +65,9 @@ FluidbookSlider.prototype = {
             $("#slider").removeClass("drag");
         }
         if (move) {
-            this.updatePageByCursorPosition(this.pageToSlider(e.center.x), end, true);
+            if (e.center != undefined) {
+                this.updatePageByCursorPosition(this.pageToSlider(e.center.x), end, true);
+            }
         }
     },
 
-- 
2.39.5