This is a very odd order entry problem that happened to me on Friday. I have never seen anything like this in 13 years of trading. I'm trying to figure out whether my broker (SureTrader) is to blame, or the software (DASTrader). At Friday near the close of trading, I accidentally placed a buy order for 800 shares of a stock. (Actually I had just closed out a short position of 800 shares, and 2 buy orders of 800 shares were placed--and I never, ever hit the order buttons twice by accident.) It was a limit order, and 550 of those shares were purchased. I didn't realize this until a little after the close. There was a large ecn bid after the market closed, so I figured I would just sell to close my position. On DASTrader, there is one button that controls sales and short sales. If you are long a stock, it says SELL, if you're flat, it says SHRT. I was long 550 shares, but for some reason the button said SHRT. I modified my order quantity to 550 shares and hit the SHRT button. I couldn't find any way to change that button to sell, or to find an alternative way to sell and not short. I got a message that I didn't have the necessary buying power to place this trade. I have never heard of not having enough buying power to close a position--it makes no logical sense. After talking with support, it was explained to me what happened. Since I only got filled on 550 shares of my 800 share order, I still had a live 250 share buy order at a limit price below the current market. So the software 'thought' that I had a 550 share position, a 250 share buy order, and a 550 share short order. And all this was beyond my buying power. (I was also told that after the close, my buying power became 2X equity instead of 6X, but from regularly trading after the close with this broker, I know that's not the case.) I am perplexed by all this. It seems that if you place an order, and it gets partially filled, you may not bet allowed to exit that position until you cancel your original order. (And I did hit the cancel button several times, and got the message that I couldn't cancel a non-existing order.) Also, it appears that the software would have allowed me to enter a new short position, for a stock that I was currently long. A lot of firms are using DASTrader now. Have any DAS users experienced this?