I should have asked about this issue a long time ago. Have been working around it for quite a while.
Right now for example I used the spot healing brush tool on a copy of the bg layer cntrl j in windows.
Now I want to use the clone tool and then reduce the opacity but I don't want the reduced opacity to effect the clone stamp.
So I made another copy cntrl j and have to put it about the previous one to the effects.
But this prevents me from seeing the effects of the healing brush tool.
Time for me to understand something which is probably so basic, but something that I never got an understanding of!
Thanks for any help,
P.S. I looked at lots of layer tutorials over the years but none that I touch on this. "you are looking down through the top layer", etc.