Hi Geof
I am not going to get into a photoshop / pixinsight discussion other than to say they are different

.
The way pixinsight approaches its processing is different to other packages and the use of masks to select area to control selected areas can take a bit of practice

Where I do agree with you is that a form of layers is going to be needed and is indeed in the pipeline ( Do not know when ) As I know you have put your desires on the pixinsight wishlist and perhaps we can get things moving for you
Anyway for me I will continue to use my Beta pixinsight for the majority of my processes
Regards Harry