Good plugin. Does what is says with minimal fuss. However, it would be great if the top level category could actually be clicked on instead of it being a toggle action for the subcategories. Would like to be able to clock on a drop down arrow or something instead. Otherwise maybe just need to put a subcategory of 'all' underneath.
Updating the plugin to use jQueryTree functionality would be an awesome upgrade https://mbraak.github.io/jqTree/
Hey BTW, did this guy (subhansanjaya) https://wordpress.org/plugins/woocommerce-collapsing-categories/ like just rip off your code and publish it as his own? As the widget looks and behaves very similar.