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Just an usability question - when I have radio button in my design, 
I can "turn it on", but can't turn it off. I know I should use check-line 
instead probably, but is it correct that single radio button can't 
be deselected, if it allows to be selected? :-)

Can someone point me to the syntax for radio-line?  and check-line?

btw: it only looks at 'input flagged controls such as field, check-line, 
drop-down, area, etc.