Category dropdown not working after adding subcategory

This plugin is particularly useful and unique.
However, it has a small problem.
When a subcategory is added to a category, the latter loses the dropdown functionality.
This is inconvenient because to build in a new subcategory in this category we must first save the publication and reload the page
The other categories, work well.

https://ww.wp.xz.cn/plugins/wp-dropdown-hierarchial-category-ui/