I just released a new version (v1.1.9) containing these:
-new buy condition: "count in hand(~cardname~)" which will allow for instance buying Cache only when you have a Trader in hand
-Trader will not be played when we're going to buy Cache (specifically hard coded behaviour)
-Tunnel bug fixed (was not always discarded first)
-Mandarin slightly modified play rules so it will always put back the best (treasure) card if it can't buy the top card in the buy list (most of the time this is Province/Colony)
You should update automatically.