Here is the fix :
Index: TradeList.java
===================================================================
--- TradeList.java (révision 4422)
+++ TradeList.java (révision 4423)
@@ -1020,6 +1020,11 @@
if (oldItem == null)
continue;
}
+ if (oldItem.getItemId() != item.getItemId())
+ {
+ Util.handleIllegalPlayerAction(player, player+" is cheating with sell items", Config.DEFAULT_PUNISH);
+ return false;
+ }
if (!oldItem.isTradeable())
continue;