Hi there,
Looks like you’re attempting to put all possible subcategory selections into one drop down menu, and then hide certain ones. That could get tricky. You may want to do something more UI-tricky, and create two sub category drop down lists. One with animals, and one with cars. The default subcategory can be shown, if you default the main category to say…animals, and then if you make the main category selection, you can hide/unhide the other drop downs accordingly. That may do the trick, but then you have to be careful in your handling code, to key on the enums that you pull out of the subcategory based on the main category. I think the trickiest part here would be the hiding and unhiding of fields.
Make sure that if you go this route, that both dropdown menus are the same size and placement, otherwise the UI might look meh, if you have components on the Snap popping in and out of view, and skewing the placement of other UI components.
Thanks,
-Charlie