Is there a different way to force the drop list to be open and closed besides setting a button inside the widget?

Hi !

I created a droplist widget and set a button inside of it to wether open the drop list or close the drop list.
I can normally open the drop list but when I click on the button again the drop list is closed and then it opens again.

Is there a different way to force the drop list to be open and closed besides setting a button inside the widget ?