Can not expand woobewoo filter backend

Hi Community!
So, today I am getting a difficulty (or bug?).
One month ago, I installed a woobewoo product filter plugin. and everything is working fine.
Until yesterday, I tried to add one more category to the filter in the backend, but the button can not expand the options to edit the settings. please see below:
https://snipboard.io/yCu1FN.jpg
here is the plugin: https://www.ads-software.com/plugins/woo-product-filter/
What Should I do?
I have tried to uninstall and install the plugin, but still the same.
I also tried emailing the developer 3 days ago, but still got no reply yet.

Thank you in advance!