Program: 30710
Project: 30710
Buggy source:
@Override protected void handleMouseClick(Slot slot,int slotIdx,int ctrlDown,int key){
  EntityPlayer player=Minecraft.getMinecraft().thePlayer;
  if (slot instanceof SlotFake) {
    InventoryAction action=null;
    action=ctrlDown == 1 ? InventoryAction.SPLIT_OR_PLACESINGLE : InventoryAction.PICKUP_OR_SETDOWN;
    if (action != null) {
      try {
        PacketInventoryAction p=new PacketInventoryAction(action,slotIdx,null);
        NetworkHandler.instance.sendToServer(p);
      }
 catch (      IOException e) {
        AELog.error(e);
      }
    }
    return;
  }
  if (slot instanceof SlotCraftingTerm) {
    if (key == 6)     return;
    InventoryAction action=null;
    if (key == 1)     action=InventoryAction.CRAFT_SHIFT;
 else     action=ctrlDown == 1 ? InventoryAction.CRAFT_STACK : InventoryAction.CRAFT_ITEM;
    if (action != null) {
      try {
        PacketInventoryAction p=new PacketInventoryAction(action,slotIdx,null);
        NetworkHandler.instance.sendToServer(p);
      }
 catch (      IOException e) {
        AELog.error(e);
      }
    }
    return;
  }
  if (Keyboard.isKeyDown(Keyboard.KEY_SPACE)) {
    IAEItemStack stack=null;
    if (slot instanceof SlotME)     stack=((SlotME)slot).getAEStack();
    try {
      int slotNum=inventorySlots.inventorySlots.size();
      if (!(slot instanceof SlotME) && slot != null)       slotNum=slot.slotNumber;
      ((AEBaseContainer)inventorySlots).setTargetStack(stack);
      PacketInventoryAction p=new PacketInventoryAction(InventoryAction.MOVE_REGION,slotNum,null);
      NetworkHandler.instance.sendToServer(p);
    }
 catch (    IOException e) {
      AELog.error(e);
    }
    return;
  }
  if (slot instanceof SlotME) {
    InventoryAction action=null;
    IAEItemStack stack=null;
switch (key) {
case 0:
      action=ctrlDown == 1 ? InventoryAction.SPLIT_OR_PLACESINGLE : InventoryAction.PICKUP_OR_SETDOWN;
    stack=((SlotME)slot).getAEStack();
  break;
case 1:
action=ctrlDown == 1 ? InventoryAction.PICKUP_SINGLE : InventoryAction.SHIFT_CLICK;
stack=((SlotME)slot).getAEStack();
break;
case 3:
if (player.capabilities.isCreativeMode) {
IAEItemStack slotItem=((SlotME)slot).getAEStack();
if (slotItem != null) {
action=InventoryAction.CREATIVE_DUPLICATE;
stack=slotItem;
}
}
break;
default :
case 4:
case 6:
}
if (action != null) {
try {
((AEBaseContainer)inventorySlots).setTargetStack(stack);
PacketInventoryAction p=new PacketInventoryAction(action,inventorySlots.inventorySlots.size(),null);
NetworkHandler.instance.sendToServer(p);
}
 catch (IOException e) {
AELog.error(e);
}
}
return;
}
super.handleMouseClick(slot,slotIdx,ctrlDown,key);
}

Fixed version (ground truth):
@Override protected void handleMouseClick(Slot slot,int slotIdx,int ctrlDown,int key){
  EntityPlayer player=Minecraft.getMinecraft().thePlayer;
  if (slot instanceof SlotFake) {
    InventoryAction action=null;
    action=ctrlDown == 1 ? InventoryAction.SPLIT_OR_PLACESINGLE : InventoryAction.PICKUP_OR_SETDOWN;
    if (action != null) {
      try {
        PacketInventoryAction p=new PacketInventoryAction(action,slotIdx,null);
        NetworkHandler.instance.sendToServer(p);
      }
 catch (      IOException e) {
        AELog.error(e);
      }
    }
    return;
  }
  if (slot instanceof SlotCraftingTerm) {
    if (key == 6)     return;
    InventoryAction action=null;
    if (key == 1)     action=InventoryAction.CRAFT_SHIFT;
 else     action=ctrlDown == 1 ? InventoryAction.CRAFT_STACK : InventoryAction.CRAFT_ITEM;
    if (action != null) {
      try {
        PacketInventoryAction p=new PacketInventoryAction(action,slotIdx,null);
        NetworkHandler.instance.sendToServer(p);
      }
 catch (      IOException e) {
        AELog.error(e);
      }
    }
    return;
  }
  if (Keyboard.isKeyDown(Keyboard.KEY_SPACE)) {
    if (enableSpaceClicking()) {
      IAEItemStack stack=null;
      if (slot instanceof SlotME)       stack=((SlotME)slot).getAEStack();
      try {
        int slotNum=inventorySlots.inventorySlots.size();
        if (!(slot instanceof SlotME) && slot != null)         slotNum=slot.slotNumber;
        ((AEBaseContainer)inventorySlots).setTargetStack(stack);
        PacketInventoryAction p=new PacketInventoryAction(InventoryAction.MOVE_REGION,slotNum,null);
        NetworkHandler.instance.sendToServer(p);
      }
 catch (      IOException e) {
        AELog.error(e);
      }
      return;
    }
  }
  if (slot instanceof SlotME) {
    InventoryAction action=null;
    IAEItemStack stack=null;
switch (key) {
case 0:
      action=ctrlDown == 1 ? InventoryAction.SPLIT_OR_PLACESINGLE : InventoryAction.PICKUP_OR_SETDOWN;
    stack=((SlotME)slot).getAEStack();
  break;
case 1:
action=ctrlDown == 1 ? InventoryAction.PICKUP_SINGLE : InventoryAction.SHIFT_CLICK;
stack=((SlotME)slot).getAEStack();
break;
case 3:
if (player.capabilities.isCreativeMode) {
IAEItemStack slotItem=((SlotME)slot).getAEStack();
if (slotItem != null) {
action=InventoryAction.CREATIVE_DUPLICATE;
stack=slotItem;
}
}
break;
default :
case 4:
case 6:
}
if (action != null) {
try {
((AEBaseContainer)inventorySlots).setTargetStack(stack);
PacketInventoryAction p=new PacketInventoryAction(action,inventorySlots.inventorySlots.size(),null);
NetworkHandler.instance.sendToServer(p);
}
 catch (IOException e) {
AELog.error(e);
}
}
return;
}
super.handleMouseClick(slot,slotIdx,ctrlDown,key);
}