Add to a parent tag - Custom Attributes

Hi! I created a custom list attribute of states (main parent) and their proper cities(subcategory). As shown in the image, when I created a subcategory I was able to choose in the Attributes options to which parent category I wanted to “merge it”, so the subcategories were shown on the front end a little bit to the right. For Example, Santiago (subcategory) “merged” to Nuevo León (parent category). And now, when I create a new “tag” attribute like “Zuazua”, i cant add it to the parent category cause the “select parent category” is gone. How can I do this?

I dont know if if I accidentally changed some settings or something. Thanks for the help!

Please make sure that there are no third-party plugins or customizations that may cause this issue, options are hierarchical by default and the Parent Category drop-down should appear.

Thanks! It was a customization that caused the issue