I understand that dynamic lookup is not possible through OOB FIM RCDC i.e filtering values for another control based on value entered previously by the user in the same request.
How I am achieving semi-dynamic nature in RCDC is through toggling of control visibility through checkbox in combination with Auto-postback property as shown in this link https://identityminded.wordpress.com/2011/10/14/fim2010-semi-dynamic-rcdc-operations/
MY QUESTION IS, why in FIM are we able to capture value of a boolean attribute through auto-postback in RCDC but not of any other type of attribute (reference, string) etc.