trashing hidden cards with Lurker

[santamonica811]

According to the text, Lurker can trash "an action" in the Supply.  It does not say "any action," but nor does it say "any visible action" or words to that effect.  In the online game, Lurker does not allow me to trash non-visible cards (e.g., split piles, hidden Knights, hidden Castles-that-are-actions, etc).  I take it that this is not a bug, yes?  [In my In-real-life games, we do not yet own this card, so I'm not sure what it's "supposed" to do per official Dominion rules.]

(My common-sense thought is:  If Lurker can really trash *any* action card--hidden or not--then it is ridiculously under-priced at 2 coins.)

[RTT]

Lurker says "in the supply" that inlcude technically only the top card of each pile at the moment you play them.

From the wiki on "supply"

Ordinarily each pile in the Supply consists of several copies of the same card. The four exceptions to this are Ruins, KnightsKnights.jpg, CastlesCastles.jpg, and Split pile cards, which are each Supply piles containing more than one differently named cards; in these cases, only the top card of the pile is visible to players and available to be bought or gained. For this reason, although the entirety of any Supply pile is physically part of the Supply, only the top card of any pile is considered to be "in the Supply". For instance, when Band of MisfitsBand of Misfits.jpg requires you to choose a "card in the Supply", you may not choose a card in the Ruins or Knights pile other than the one on top.

[santamonica811]

RTT,
Much thanks.  Crystal-clear explanation.