Program: 173836
Project: 173836
Buggy source:
public void actionPerformed(ActionEvent actor){
  JComponent source=(JComponent)actor.getSource();
  if (source instanceof ClickField) {
    gbc=gb.getConstraints(source);
    itemIndex=gbc.gridy - bidPerPlayerYOffset;
    BuyOrBidStartItem currentActiveItem=(BuyOrBidStartItem)((ClickField)source).getPossibleActions().get(0);
    if (currentActiveItem.getStatus() == StartItem.BUYABLE) {
      buyButton.setEnabled(true);
      buyButton.setPossibleAction(currentActiveItem);
      if (includeBidding) {
        bidButton.setEnabled(false);
        bidAmount.setEnabled(false);
      }
    }
 else     if (currentActiveItem.getStatus() == StartItem.BIDDABLE || currentActiveItem.getStatus() == StartItem.AUCTIONED) {
      buyButton.setEnabled(false);
      if (includeBidding) {
        bidButton.setEnabled(true);
        bidButton.setPossibleAction(currentActiveItem);
        bidAmount.setEnabled(true);
        int minBid=items[itemIndex].getMinimumBid();
        spinnerModel.setMinimum(new Integer(minBid));
        spinnerModel.setValue(new Integer(minBid));
      }
    }
  }
 else   if (source instanceof ActionButton) {
    PossibleAction activeItem=((ActionButton)source).getPossibleActions().get(0);
    if (activeItem instanceof BuyOrBidStartItem) {
      BuyOrBidStartItem action=(BuyOrBidStartItem)activeItem;
switch (action.getStatus()) {
case StartItem.BUYABLE:
        process(action);
      break;
case StartItem.BIDDABLE:
case StartItem.AUCTIONED:
    action.setActualBid(((Integer)spinnerModel.getValue()).intValue());
  process(action);
break;
case StartItem.NEEDS_SHARE_PRICE:
if (requestStartPrice(action)) process(action);
break;
}
}
 else if (activeItem instanceof NullAction) {
process(activeItem);
}
}
displayError();
}

Fixed version (ground truth):
public void actionPerformed(ActionEvent actor){
  JComponent source=(JComponent)actor.getSource();
  if (source instanceof ClickField) {
    gbc=gb.getConstraints(source);
    itemIndex=gbc.gridy - bidPerPlayerYOffset;
    BuyOrBidStartItem currentActiveItem=(BuyOrBidStartItem)((ClickField)source).getPossibleActions().get(0);
    if (currentActiveItem.getStatus() == StartItem.BUYABLE) {
      buyButton.setEnabled(true);
      buyButton.setPossibleAction(currentActiveItem);
      if (includeBidding) {
        bidButton.setEnabled(false);
        bidAmount.setEnabled(false);
      }
    }
 else     if (currentActiveItem.getStatus() == StartItem.BIDDABLE || currentActiveItem.getStatus() == StartItem.AUCTIONED) {
      buyButton.setEnabled(false);
      if (includeBidding) {
        bidButton.setEnabled(true);
        bidButton.setPossibleAction(currentActiveItem);
        bidAmount.setEnabled(true);
        int minBid=items[itemIndex].getMinimumBid();
        spinnerModel.setMinimum(new Integer(minBid));
        spinnerModel.setValue(new Integer(minBid));
      }
    }
  }
 else   if (source instanceof ActionButton) {
    PossibleAction activeItem=((ActionButton)source).getPossibleActions().get(0);
    if (activeItem instanceof BuyOrBidStartItem) {
      BuyOrBidStartItem action=(BuyOrBidStartItem)activeItem;
switch (action.getStatus()) {
case StartItem.BUYABLE:
        process(action);
      break;
case StartItem.BIDDABLE:
case StartItem.AUCTIONED:
    action.setActualBid(((Integer)spinnerModel.getValue()).intValue());
  process(action);
break;
case StartItem.NEEDS_SHARE_PRICE:
if (requestStartPrice(action)) process(action);
break;
}
}
 else if (activeItem instanceof NullAction) {
process(activeItem);
}
}
}