I was holding a volume of 0,6 Lot in Sell and 0,48 Lot in Buy, and at rollover time the chart was showing some movements (10 pips up and down) on GBPUSD, but it was going almost in a straight line, and suddenly in a few seconds I lost aprox. 200€ of free margin forcing the closure of all my positions. On normal situation it shouldn't have mattered much if it went upwards or downwards, but suddenly both sides where going against me!