The issue is that it does not occur frequently but when it happens then it is always in connection with displaying pictures. It could well be that it has something to do with the provider of my radio signal (live in a rural area). With pictures I mean a sequence of pictures, i.e. 12 pictures go perfectly, and the 13th will not come up. Restarting the sequence will correct this. It is not a major issue for me but a bit annoying. Have now FF 3.6.2 installed.