Search multiple checkbox by dropdown

Hi, I have an issue with multiple checkbox field in the userlist search.

I followed your video tutorial n. 19, where a multiple checkbox field ('cb expertise' in the tutorial example) is searchable in the userlist by a single dropdown.
But when I set the multiple checkbox field as searchable, in the userlist search it's not displayed a single dropdown, but the same checkboxes: I have to check the boxes instead of selecting from a menu the value I want to search for.

I need to use checkbox to select multiple activities for a single profile, but I want the user to search these activities once at a time, by a single dropdown, exactly as shown with the 'cb expertise' field in your tutorial at 9:20:

What am I missing?
Thank you

The dropdown usage is Advanced search mode. That can be enabled within your userlist parameters, which defaults to simply any search mode.

Thank you. I didn't notice it in the video tutorial. So is there no way to search with a single dropdown a multiple field, right?

Correct, there's no single dropdown usage for a multiselect field.