Blox Drop Down mutli selection

I have a Blox dropdown filter that is one selection at a time.

I would like to make it multi select but the only link I can find is here: https://community.sisense.com/t5/knowledge/multi-select-dropdown-list-filter/ta-p/9595

Is there a way to make the current format and drop down into a multi select? This seems like it should be a basic and easy task to accomplish. What have others implemented to obtain the multi select functionality?

I have also attached the current json from the editor pane. Any help is appreciated.