How to write an EL expression to read the value of a dropdown field?

Content

I'd like to display a field depending on the value of another field.

I can easily do this for text fields.

But when there is a dropdown (either LOV or not) I cannot access the value using EL. Does anyone know how to do this?

(Specifically on the Supplier Registration page I want to enable the Tax Registration Number field ONLY when Tax Organization = Corporation).

Version

21A