Added missing check for callback if page never scrolled

diff --git a/wcfsetup/install/files/js/WoltLabSuite/Core/Ui/Scroll.js b/wcfsetup/install/files/js/WoltLabSuite/Core/Ui/Scroll.js
index 919f869f31387bd6134a66f13d6e654da1949001..ace1b9f6a7f3af9b899564d69fd032ee03cff239 100644 (file)
--- a/wcfsetup/install/files/js/WoltLabSuite/Core/Ui/Scroll.js
+++ b/wcfsetup/install/files/js/WoltLabSuite/Core/Ui/Scroll.js
@@ -82,7 +82,7 @@ define(['Dom/Util'], function(DomUtil) {
                        if (_timeoutScroll !== null) window.clearTimeout(_timeoutScroll);
                        
                        _timeoutScroll = window.setTimeout(function() {
-                               _callback();
+                               if (_callback !== null) _callback();
                                
                                window.removeEventListener('scroll', _callbackScroll);
                                _callback = null;