Program: 51648
Project: 51648
Buggy source:
@Override public void simpleMode(InventoryClickEvent event){
  System.out.print("String_Node_Str");
  boolean top=event.getView().convertSlot(event.getRawSlot()) == event.getRawSlot();
  Player player=(Player)event.getWhoClicked();
  int slot=event.getSlot();
  System.out.print(slot);
  if (slot < 0) {
    if (event.getCursor().getTypeId() != 0) {
      BankItem item=getSelectedItem();
      if (item != null) {
        if (item.getSlot() != -1) {
          if (!withdrawFee(player)) {
            player.sendMessage(locale.getLocaleString("String_Node_Str"));
            event.setCancelled(true);
            return;
          }
          player.sendMessage(locale.getLocaleString("String_Node_Str","String_Node_Str"));
          removeItemFromAccount(item);
          selectItem(null);
        }
      }
      return;
    }
  }
  if (top) {
    if (rowClicked(getTab().getTabSize() + 1,slot)) {
      if (event.getCurrentItem().getTypeId() != 0) {
        if (event.getCursor().getTypeId() == 0) {
          if (!getTab().getName().equals(getTab(getRowSlot(slot)).getId())) {
            setTab(getTab(getRowSlot(slot)).getId());
            player.sendMessage(locale.getLocaleString("String_Node_Str").replace("String_Node_Str",getTab().getName()));
            switchInventory();
          }
        }
 else {
        }
        event.setCancelled(true);
        return;
      }
    }
 else {
      if (event.isShiftClick()) {
        BankItem item=getSelectedItem();
        if (selectItem(slot).hasSelectedItem()) {
          if (!this.playerInventoryHasPlace(player)) {
            player.sendMessage(locale.getLocaleString("String_Node_Str","String_Node_Str"));
            event.setCancelled(true);
            selectItem(item);
            return;
          }
          if (!withdrawFee(player)) {
            player.sendMessage(locale.getLocaleString("String_Node_Str"));
            event.setCancelled(true);
            selectItem(item);
            return;
          }
          player.sendMessage(locale.getLocaleString("String_Node_Str","String_Node_Str"));
          event.setCurrentItem(null);
          removeItemFromAccount(getSelectedItem());
          addSelectedToPlayerInventory(player);
          event.setCancelled(true);
        }
        selectItem(item);
        return;
      }
      BankItem item=getSelectedItem();
      selectItem(slot);
      System.out.print(item);
      if (item != null) {
        System.out.print(item.getSlot());
        if (item.getSlot() == -1) {
          if (!depositFee(player)) {
            player.sendMessage(locale.getLocaleString("String_Node_Str"));
            event.setCancelled(true);
            selectItem(item);
            return;
          }
          player.sendMessage(locale.getLocaleString("String_Node_Str","String_Node_Str"));
          item.setSlot(slot);
          item.getItemStack().setAmount(event.getCursor().getAmount());
          addItemToAccount(item);
          item=null;
        }
      }
      if (item != null) {
        BankItem oldItem=toBankItem(item.getItemStack());
        player.sendMessage(locale.getLocaleString("String_Node_Str","String_Node_Str"));
        oldItem.setSlot(item.getSlot());
        item.setSlot(slot);
        updateAccountItem(oldItem,item);
      }
    }
  }
 else {
    System.out.print("String_Node_Str");
    if (event.isShiftClick()) {
      BankItem item=getSelectedItem();
      if (selectItem(toBankItem(event.getCurrentItem())).hasSelectedItem()) {
        if (!bankerInventoryHasPlace()) {
          player.sendMessage(locale.getLocaleString("String_Node_Str","String_Node_Str"));
          selectItem(item);
          event.setCancelled(true);
          return;
        }
        if (!depositFee(player)) {
          player.sendMessage(locale.getLocaleString("String_Node_Str"));
          event.setCancelled(true);
          selectItem(item);
          return;
        }
        player.sendMessage(locale.getLocaleString("String_Node_Str","String_Node_Str"));
        addSelectedToBankerInventory();
        event.setCurrentItem(null);
      }
      selectItem(item);
      return;
    }
    BankItem item=getSelectedItem();
    if (item != null) {
      if (item.getSlot() != -1) {
        if (!withdrawFee(player)) {
          player.sendMessage(locale.getLocaleString("String_Node_Str"));
          event.setCancelled(true);
          return;
        }
        player.sendMessage(locale.getLocaleString("String_Node_Str","String_Node_Str"));
        removeItemFromAccount(item);
      }
    }
    if (selectItem(toBankItem(event.getCurrentItem())).hasSelectedItem())     getSelectedItem().setSlot(-1);
  }
}

Fixed version (ground truth):
@Override public void simpleMode(InventoryClickEvent event){
  System.out.print("String_Node_Str");
  boolean top=event.getView().convertSlot(event.getRawSlot()) == event.getRawSlot();
  Player player=(Player)event.getWhoClicked();
  int slot=event.getSlot();
  System.out.print(slot);
  if (slot < 0) {
    if (event.getCursor().getTypeId() != 0) {
      BankItem item=getSelectedItem();
      if (item != null) {
        if (item.getSlot() != -1) {
          if (!withdrawFee(player)) {
            player.sendMessage(locale.getLocaleString("String_Node_Str"));
            event.setCancelled(true);
            return;
          }
          player.sendMessage(locale.getLocaleString("String_Node_Str","String_Node_Str"));
          removeItemFromAccount(item);
          selectItem(null);
        }
      }
      return;
    }
  }
  if (top) {
    if (rowClicked(getTab().getTabSize() + 1,slot)) {
      if (event.getCurrentItem().getTypeId() != 0) {
        if (event.getCursor().getTypeId() == 0) {
          if (!getTab().getName().equals(getTab(getRowSlot(slot)).getId())) {
            setTab(getTab(getRowSlot(slot)).getId());
            player.sendMessage(locale.getLocaleString("String_Node_Str").replace("String_Node_Str",getTab().getName()));
            switchInventory();
          }
        }
 else {
        }
      }
      event.setCancelled(true);
      return;
    }
 else {
      if (event.isShiftClick()) {
        BankItem item=getSelectedItem();
        if (selectItem(slot).hasSelectedItem()) {
          if (!this.playerInventoryHasPlace(player)) {
            player.sendMessage(locale.getLocaleString("String_Node_Str","String_Node_Str"));
            event.setCancelled(true);
            selectItem(item);
            return;
          }
          if (!withdrawFee(player)) {
            player.sendMessage(locale.getLocaleString("String_Node_Str"));
            event.setCancelled(true);
            selectItem(item);
            return;
          }
          player.sendMessage(locale.getLocaleString("String_Node_Str","String_Node_Str"));
          event.setCurrentItem(null);
          removeItemFromAccount(getSelectedItem());
          addSelectedToPlayerInventory(player);
          event.setCancelled(true);
        }
        selectItem(item);
        return;
      }
      BankItem item=getSelectedItem();
      selectItem(slot);
      System.out.print(item);
      if (item != null) {
        System.out.print(item.getSlot());
        if (item.getSlot() == -1) {
          if (!depositFee(player)) {
            player.sendMessage(locale.getLocaleString("String_Node_Str"));
            event.setCancelled(true);
            selectItem(item);
            return;
          }
          player.sendMessage(locale.getLocaleString("String_Node_Str","String_Node_Str"));
          item.setSlot(slot);
          item.getItemStack().setAmount(event.getCursor().getAmount());
          addItemToAccount(item);
          item=null;
        }
      }
      if (item != null) {
        BankItem oldItem=toBankItem(item.getItemStack());
        player.sendMessage(locale.getLocaleString("String_Node_Str","String_Node_Str"));
        oldItem.setSlot(item.getSlot());
        item.setSlot(slot);
        updateAccountItem(oldItem,item);
      }
    }
  }
 else {
    System.out.print("String_Node_Str");
    if (event.isShiftClick()) {
      BankItem item=getSelectedItem();
      if (selectItem(toBankItem(event.getCurrentItem())).hasSelectedItem()) {
        if (!bankerInventoryHasPlace()) {
          player.sendMessage(locale.getLocaleString("String_Node_Str","String_Node_Str"));
          selectItem(item);
          event.setCancelled(true);
          return;
        }
        if (!depositFee(player)) {
          player.sendMessage(locale.getLocaleString("String_Node_Str"));
          event.setCancelled(true);
          selectItem(item);
          return;
        }
        player.sendMessage(locale.getLocaleString("String_Node_Str","String_Node_Str"));
        addSelectedToBankerInventory();
        event.setCurrentItem(null);
      }
      selectItem(item);
      return;
    }
    BankItem item=getSelectedItem();
    if (item != null) {
      if (item.getSlot() != -1) {
        if (!withdrawFee(player)) {
          player.sendMessage(locale.getLocaleString("String_Node_Str"));
          event.setCancelled(true);
          return;
        }
        player.sendMessage(locale.getLocaleString("String_Node_Str","String_Node_Str"));
        removeItemFromAccount(item);
      }
    }
    if (selectItem(toBankItem(event.getCurrentItem())).hasSelectedItem())     getSelectedItem().setSlot(-1);
  }
}