AnythingSlider can't select category

I installed AnythingSlider for WordPress through dashboard. When i try to add a slide, i get this:
Image link

And i can’t select a category, and if i set cat=my-category it still doesn’t work. So it doesn’t matter if i set it manually or not, it doesn’t show the category posts.

Can anybody help me?

https://www.ads-software.com/plugins/anythingslider-for-wordpress/

And if i want to see the cancel and the insert slide buttons i must edit the AnythingSlider appearance.