Hi, I need your help. Monday, 6th october, I submited 2 orders on the TWS Interactive Brokers. The first was the Parent order and was for a Buy of 2000 DNDN (Nasdaq stock) at 4.67$ Limit. The 2nd was a Child (only submited if the parent is filled), and was for a Sell of 2000 DNDN at 5.13$ Limit. Few seconds later,at 9:45, the Parent order is filled, and I was Long of 2000 shares of DNDN at 4.65$. 5 minutes later, at 09:50, as the price raised quickly, the Sell order is filled at 5.13$, and I was happy to have a P/L of +960$. But, 15 minutes later, at 10:05, I saw on my IB account that I was short of 2000 DNDN at 5.13$. At this moment, the last was at 7.11$. 5 minutes later, at 10:10, I received a message telling me that "NYSE/ARCA has ruled to cancel all trades in DNDN between 9:45:00 and 9:48 ET due to a regulatory halt". At this moment, I had an unrealized P/L of more than -3000$. As it was the first time that this arrived to me, I didn't know if I was really short or not? Is IB going to regularize or not (by cancelling the sell order)? Few hours later when I received the Statement, the Short position was confirmed. I closed my position at the next Open at 6.65$ --> loss of -3000$. I understand that a trade can be cancelled AFTER it has been filled, that's the (bad) rules. But, don't you think that the broker have the obligation to cancel also the close order, as I was flat at the moment of the cancel? I open a "ticket" at IB message center but don't have answer at the moment. What can I do? Thanks for your help and for sharing your experience.