Per_page attribute

If I don’t select any folder in tinybutton menu I get the multi page menù with the selected number of document per page. If I select a folder the plugin displays a number of documents equal to the per_page attribut but only the first ‘per_page? number without the possibility to go to the second page and so on. Is possible to solve this problem? Thankyou.

https://ww.wp.xz.cn/plugins/issuu-panel/