Thanks for that explanation Dan.
I could have done with knowing that today. I planned to fly IFR and got throught the business of finding the runway and getting radio permission to take off. But then I didn't receive any instructions for about 20nm and was getting a bit concerned. I might just as well been flying VFR.
Don't know how I did it but then I found I was unintentionally flying VFR and then couldn't get back to IFR.
I fiddled about and then the program packed up, so frustrated, I did something else for the rest of the afternoon.
John