Thank you rrr_hhh, I was hoping for just such a clear explanation, just what I needed.
......although when I set multifunction to fn2, I do not get multifunction! On one camera I get WB and the other I get the exposure curve adjustment and on the other I get WB. however if I set fn2 to magnify it works perfectly!
I may not be able to answer for a few days ..as there'll be no Internet --