Category List

We have a large list of categories. The category list is so long that it is impossible for users to scroll down the long list of categories to find anything. Is there a way to organize the categories so you can click to expand top level categories and again on sub categories if you want to see them, or click again to close them. I have seen this on other directory programs but it seems this is missing from PremiumPress. The same issue happens on the submit page when you have to choose the category you want to submit to. If someone has a large list of categories it is impossible to use and not get lost in the list.