sequencedcollection Method findFirst
Send aMessage for each element within this collection,
passing the element to the invoked method until one of the
elements causes lnkMessage to return true.
aMessage should be a CallBack pointing to a method which
expects an element as a parameter and will return a pic x
If the CallBack returns True (that is 1), then the index of
the element that caused this is returned in anindex and
lnkMessage is not sent to any more elements.
If no element causes lnkMessage to return true then zero is