So I'm advising from a cell phone which means that with regards to javascript/jquery/css I can't be 100% sure that I have all the info correct, but what I see in review of the source code for the dropdown menu is that if an item has sub-items to it, then the item has the class submenu, but then it's sub-items has a class the next level down. Ie. The first dropdown/popout has a level2 class, the categories under that which have additional sub-categories are captured as level3 after the class link is assigned a submenu class. Product that don't have a sub-category have no class assigned. So, it looks like in order for clicking your sub-category to act like the dropdown arrow on the right side of the list, that the submenu class either needs to be replaced by the applicable next level class or the next level class needs to be included with the submenu class. I'm not exactly sure what all is involved with the submenu class (there's that cell phone limitation part) and how it is "referenced" or its importance.
So the question asked was how to find it.
May I present to you the developers toolkit. In the admin, under tools, there is a listing called developers toolkit. It can be your friend because you should be able to search on the word submenu and at least find code examples of where/how it is used. It could be in a php file, it could be in javascript, not sure at the moment because haven't cross referenced a functional site to identify this part. But it would help others I'm sure if it gets identified once found.
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