@ MrMinerVa

make sure that on the first tab (=settings) when the trader is open the "refresh orderbook every x seconds" is checked and also make sure that this value is lower than your ping-pong-time value. new orders as well as deleting your old orders happens in cycles (not instant when another guy places an order into the orderbook), and the cycle is the amount of time between "max interval" and "min interval".