from the online TWS help (Transmit an Order): DARK BLUE indicates that a simulated order type has been accepted by the IB system and that this order has yet to be elected. The order is held in the IB system (and the status remains DARK BLUE) until the election criteria are met. At that time the order is transmitted to the order destination as specified (and the order status color will change).
Not 100% sure. But imagine that during RTH it sits over on Globex's equipment and in the Overnight it moves back to the IB servers.
Whenever you are unsure of the status of an order it's always best to contact a brokers helpdesk immediately. A dim view is taken of clients that attempt to use a free option - (and you'd be surprised how many do). (Michael, I'm ok, thanks. Its a nice 84 degrees today in HK - but a little cloudy)
Thu May 6 04:40:54 2004 EST Dear Trader Please be informed that the status of native Stop and native Stop Limit orders are currently being displayed in dark blue rather than green. However these orders are live at the exchange. IB Customer Service