Currently, when you create a new note or todo item and "Custom order" sort is selected, the new note appears at the bottom of the list.
If you create multiple new items in a row, before reordering, then the newer ones appear near the bottom, just above the others you have recently created.
When you change the sort order, this "recency" is reset - the next new item appears at the bottom again.
(there is also a bug where when you change the sort order, those recently created items "pop" to the top, detailed at With Custom Sort, new notes appear at bottom and later randomly "pop" to the top · Issue #7741 · laurent22/joplin · GitHub with a proposed fix in Desktop: Fixes #7741: initialize order without moving notes by TaoK · Pull Request #7765 · laurent22/joplin · GitHub)
I would argue that this behavior is surprising and not great: The "new notes appear at the bottom unless you just created new notes" behavior is surprising/confusing, and more generally, when I create a note and I had a note selected, I would expect the note I am creating to appear just above, or just below, the note that was selected.
In other words, if I am editing a todo item, and hit Ctrl-T, I would expect the new note (if I'm in Custom order sort) to appear above or below the note I was editing.
Is this something we should be comfortable changing, as a simple enhancement, or would this warrant a configuration setting?
If we did introduce a configuration setting, what would the options be?
The options I can imagine for "new item position" would be:
- Top
- Above selected item(s)
- Below selected item(s)
- Bottom
Personally I would happy with either of "Above selected item(s)" or "Below selected item(s)" as the single not-configurable behavior, but I'd like to get opinions before I attempt to propose a pull request.
Given the sorry state of support for custom sort, I suspect few people use it, but I'm new here so I thought I'd ask anyway 
Thanks,
Tao