I think we’re going in circles. Maps in Tinderbox are flat - a single unbounded 2D plane. If the user chooses to create child notes to a note, then the child moves to another note.
Also, you can have notes with children but no viewport:
Leaving aside rich text edit-in-place of $Text in the icon, much of what asked for might use much of existing maps but if a way contrary to most current use. Tis is why I suggested using a different view
albeit another map type. Thus it might re-use much of the existing map code but disable certain features, e.g. not allow note nesting in-view and suppress drill down for containers (as map items might legitimately have children e.g. for use in other view types.
‘Other view types’ also makes the point that whilst many apps have only a single view—however rich that view is. In turn that sets very firm limitations as to how we interest with our data. Tinderbox’s multiple views are a rarity but useful and powerful. Thus having a view that uses Heptabase-type constrains might be an easier way to resolve adopting such functionality. Trying to shoe-horn two similar seeming but actually different layout approaches into one view seems like a recipe where one size fits no one well.
I guess one could enforce certain containers as Heptabase only and not allow the children to have any children. But that seems more effort than the suggestions above. If you can’t create a child by drag nesting or other actions, inside the heptabase-style map then you only get children if you do things elsewhere in the doc in other views. Plus if the heptabase-style map doesn’t indicate the presence of children, even were they to exist, no harm if done. Thus, the heptabase-process-based user works their map unbothered by the presence of unseen children, and elsewhere normal maps still function as at present
As regards title, why not simply treat the first (heuristic) sentence of a new note on a heptabase-style map as the title $Name). Plenty of existing users employ sentence length titles rather than terse ones. On map title and text merge and are drawn as one (i.e. the text on the icon is $Name+" "+$Text. Editing the first sentence of the icon text alters the $Name, otherwise, the $Text of the note. In the text pane we now have the title Tinderbox expects/needs and can use on all other means of use, whilst the map still has the ‘single text’ demanded by the Heptabase method. This also allows users to work with both types of maps.