Help text not working in pdf form using AR or Chrome

In creating a PDF form with Writer; and using both a “label” and an “image button”, in control properties for each I add “Help Text”.
In Writer, the help text I create shows up as it should. But, after exporting to a PDF, the “Help Text” does not appear on hover or clicking or anything; using Acrobat Reader or Google Chrome. I’ve tried exporting as a Hybrid and FDF and HTML, as well as, PDF, still no “Help Text”. I’m pretty sure it’s user error. Can anyone help, offer suggestions or link me to an answer? Thanks