Hello!
Currently it's not possible to do that.
What you can do, if after showing the dropdown menu (after the user clicked), you could get the Dropdown panel that was instantiated, and go through every children to find the text components you want, and then change the text size...
But we're currently rewriting some components, and that's something you'll be able to do in the future :)
Can't say when though... sorry.
~ Yohan
