My son has a faulty Bosch combi microwave oven/grill, which will be replaced in a few days, under warranty. The problem he has always had is that he can't grill with the door open, like you would with a normal grill. We can't find any reviews relating to this. Could it be why the microwave has developed a fault? Or is it right that you can't grill using a combi microwave with the door open?