I personally like to always see the full note for the top item in the current view. I use long notes a lot (a small essay for each note). I use “1st line” view by default because my list would be unreadable with all notes expanded. But I find it frustrating that the note I’m editing collapses to a single line every time I click outside it (sometimes accidentally). Having the top item never collapse would solve this as I can just zoom in to any item to edit the note.
But… my preferred alternative (scope creep warning) would be:
Change the note settings to be an item attribute rather than a document attribute and make it really easy to toggle any item between “show”, “1st line”, or “hide” (preferrably a single click or keyboard shortcut to toggle). This would allow showing full notes for specific items in the list while showing 1st line or hiding notes of other items. To be usable this would also require a way to change note settings of multiple selected items together.
But I get if that is a level of complexity it may be preferable to avoid for most users and I’d be super happy just to change the behaviour of “1st line” to show the full note for the top item (this is the behaviour in Workflowy, by the way). Cheers.