Dropdown Toggle Button + Dynamic Attribute (Class Toggle)

I’ve created new page and added container and dropdown.
Wanted to check if class toggle works but Data Bindings windows is empty.

When I added a regular button it shows on the data bindings list but then it do not work as dropdown toggle button. As soon as I add “dropdown-toggle” class to the regular button it vanishes form the Data Bindings list.

How to make a

to appear on Data Bindings list ? what are to rules ? what lands on the list and what not ?
how to make class toggle when dropdown is open ?
Community Page
Last updated: