I accidentally placed an order this morning, then the market rallied against my position, it eventually fell back and I got out without a loss. That makes me think how to prevent such accidents. One way I found is to set the low and medium fat finger limits to 1 when you don't trade. If your order qty is above 1, it will give you a warning message. Remove the limits when you are ready to trade. The high fat finger limit should always be there to put a ceiling on the qty.