Hey @ronald,
It jumps the page to where the selection is.
So, let's say you've scrolled to the top of the page, but you have a selection out of sight at the bottom of the page.
Jump-to-Selection will jump to where the selection is and make it visible.
I was under the impression that your radio button was out of sight, but perhaps I was wrong.
In any case – you should be able to use PageDown instead of Space.
Look in the log.
Open the Keyboard Maestro Engine Log in the Console or BBEdit
-Chris