How does Stack/Queue Contains work?

There is an action called Stack/Queue Contains, but the help file does not have anything on it.  It seems to act like an IF statement, i.e. if the stack contains a certain value, then a return code of some sort can be placed into another value.  Is this correct?  If so, what values get placed into the return code variable?  Something like TRUE/FALSE, or 1/0, or even Y/N?  I want to see if my queue contains an email address before I decide to add that email address to it.  Is there a different action I should be using?

Thanks,

Jonathan

The action does not act as an If action (it probably should have been written that way, not sure why it wasn’t but changing it now would break existing projects). It puts either True or False in the selected variable.