1) Using IB DDE API, when maximum market Data lines are reached (ususlly a warning message will show), some of the bid/ask data are still shown but they are never updated. But you cannot know which data lines have the problem. Only by comparing the TWS data, you can detect the error. IB, could you please correct this error so that data line not showing the real time data will show value of 0. 2) Anyone else see this kind of error? how do you detect it? 3) With IB gateway, there is no way to detect this kind of error. Any thoughts? suggestion