Sort Images in Gallery

When I want to sort the images in a gallery in a custom order, the images don’t display in the Dashboard area. So it’s impossible to sort them. It worked fine in the previous version of the plugin.

I’m using version 1.9.23 on WP 4.0.
I tested this in Firefox and in Chrome.

Any suggestions?

https://www.ads-software.com/plugins/nextcellent-gallery-nextgen-legacy/