Thank you. The reality is that I VERY rarely use it as an oven or grill. I mostly use it for microwaving only. Could the microwave antenna be faulty and, if so, what I can do about it ?
OK - have never used popcorn in this microwave. But my original query referred to specifically the fact that the glass seemed to go NOT when I was microwaving but when I had used the grill facility. Even though I have only rarely used the grill facility - in a sequence of no more than five days in a row to cook bacon, it has blown.