[stumped]

what i saw is the previous screenshot. on that screen I can optionally turn on author grouping by 1st name, that changes the left side of the screen but the 7 thumbnails & book info entries on the right are unaffected.
I have done that as a new attachment.
From the feedback supplied hereI am confident that author grouping on letters works by author surname somehow, but the a-z of books on device is using the ( hidden) author srot supplied by calibre.
NB I always use connect to content server for transfers , not connect as wireless - dunno if that is a factor.
in this new screen shot - he author groupings shows 3 x H, 1 x L, 0 x P
but we now know that Peter Helton has an (wrong) author sort of Peter Helton, so it is sorted as a P in the thumbnails column, below Lallo, but counted as an H in the author grouping

so the screen in its entirety appears to contradict itself. it maybe only happens with content server, not with wireless device ?
does that make sense now ?