The common definitions.sbi includes
$EVENT:ACCEPTED$ and $EVENT:NEWSELECTION$

But I can't find anything about them in the PDF Help or Learning SB.

Do these relate to the Dialogs?

I have a Radio Button Dialog, and depending on user selection a fairly long process is carried out.
I want to avoid this process being carried out more than once, so I want to ignore the event when user clicks Radio Button, and just do it when user clicks NEXT.