Although, when you look at the server side of things, that value has to be calculated for every folder, thus an additional
count(*) statement (which requires a table scan - very bad for perf) has to be executed. Thus the runtime changes from O(N) to O(N*M). M is the average number of notes per folder.
I’m not convinced that such an edge case warrants the perf impact for everything else. But hey, I’m not the owner, so it’s not my call. Such an impact is only acceptable, when requested (by a flag, endpoint alteration, …) and should not be done by default. I’ve been a long time in performance and I’m just saying that you should be aware of the consequences. It might not matter if you have a few notes, but it will be noticeable, if you have a a lot of notes and folders.
So the overhead you have experiennced when doing it manually, will now be done by the server - every time someone request a list of folders.