no navigation arrows and preview pictures

Hi,

i have installed BlueImp on some wordpress-sites which actually don’t show the navigation overlay on fullscreen. I just can swipe by dragging or with the right/left-key.

The Problem is on all sites – also the sites which worked well at my last test.

e.g.:

https://www.stadtansichten-wernigerode.de
(Gallery in the middle of the site)
https://www.elbingerode-vorschau.wagnergraphics.de/gemeindeleben/kinder-und-familien/

Thanks for help
Torsten