If anyone from IB is reading this, hopefully this is made a reality soon. REL and SNAP are allowed but MIDPRICE is not...
The ability to submit MIDPRICE orders with attached conditions is available in TWS Beta. Unfortunately, I do not have a set date as to when it will be available in TWS Latest.
Received auto-update for TWS stable version with new Build number 972.1w earlier today. BTW there is no update note for this auto-update, it simply updated when you launch TWS. Their s/w release page has no details. https://www1.interactivebrokers.com/en/?f=/en/general/tws-notes-963.php It has messed up with Hotkey setups. 1) It is opening up Order Ticket Quote Panel for orders with Bid/Ask midpoint hotkey defeating the hotkey purpose. 2) It is using "Last" price though your hotkey set up refers to "Bid" or "Ask" price, for stock as well as options trading. Hope this gets fixed. Thanks