Thanks to all — this is becoming clearer to me. I believe my initial confounding of Separator Notes with Titled Separator Notes has produced some confusion in this thread. I’m going to try to clarify that, while responding to the several remaining contributions. Thanks to each of you for replying.
First, let me list the answers to the questions I originally posted:
1.] There is not an easier way to toggle the state of a Note to/from being a Separator Note other than via the Inspector. One suggestion is, if this is important, to create my own key-binding. Another suggestion — iirc, this was posted by Paul and subsequently deleted — was to use a Tinderbox Stamp to either change the state of a Note to a Separator Note or the toggle between the two states. I’m sorry he deleted his post.
3.] (listed out of order because #2 is complicated) Nothing is lost, as far as anyone knows, when the state of a Note is changed from “regular” to Separator and/or back. This is good to know.
2.] Here some explanation may be helpful. I’m not experimenting with, nor do I expect to have any use for, Un-Titled Separator Notes. (In an attempt at clarity, I am going to refer to Un-Title Separator Notes as Separator Lines.) Separator Lines show as lines in the Outline Pane of Outline View. Separator Lines may have children. (This complicates things.) Of course, if they have no children, they are not containers, and it makes excellent sense that they don’t show in the Map Pane of Map View. Once they do have children, though, they become containers, in which case it makes conceptual sense for them to be represented as containers in Map View. I am not arguing yet that they should — just that it makes sense for them to.
Marc has provided an illuminating history of the Separator. Does anyone know why Separator lines were considered a better solution to grouping siblings than regular Notes? (The grouping of siblings in an outline is done by adding parents as siblings and thus creating another level.)
Note again that I was not thinking of Separator Lines in my OP. Separator Lines with no children provide no utility I was interested in for the representation of the Outline of my Notes; Separator Lines with children was such an odd conception to me that after testing that one could be created I never made one again.
At the same time, I very much liked the visual representation of parent Notes in my Outline as Titled Separator Notes. There is something useful to me in visually prioritizing parents (they are, after all, containers — a characteristic nicely echoed in the boxed title). So I went about changing the state of each of the parents in my growing Tinderbox test document from a regular Note to a Titled Separator Note. My outline was good-looking, informative, and functional. Until I discovered that all Separator Notes are unavailable for display in Map View. (In primping my Outline I had excised more than half of Tinderbox’s faculties.) I was perplexed, and came here and asked: why is this so? In essence … what was I missing?
I will now present an argument for why Titled Separator Notes with children should show in Map View as regular container Notes with a viewport.
In this context Separator Notes have four states:
. No Title, no children
. No Title, children
. Title, no children
. Title, children.
Taking them in turn.
Separator Notes with no Title and no children appear as lines in Outline view and would be meaningless in Map View. They should not show in Map View.
Separator Notes with no Title and children appear in Outline view as a line with Notes indented below it. This is, to me, analogous to a file folder in a file cabinet that holds papers but is not itself labeled. This construction is generally regarded as undesirable (according the history Mark gave us, it was never the developer’s intent that such a thing exist). Even electronically as outline items, they are a weird entity (imho) that should be dealt with arbitrarily. (Pat, above, mentions using them for commentary that appears only in Outline View, which seems an excellent use of them.) They could appear in Map View.
Titled Separator Notes with no children show in Outline View as a kind of in-line label. Labelling entities that group or separate is good practice. To me they are slightly more useful than Separator Notes with no Title and no children, but they remain — if you’ll allow me — simple Outline View adornments. They should not show in Map View.
Titled Separator Notes with children are a different entity entirely. They are containers. They show in Outline View as containers with a visually prioritized label. The Notes they contain (their children) are as much a part of both the Outline and the Tinderbox document as any other Note. I propose that those Notes, and their children, show in Map View with the same functionality of other container Notes: as a drill-down-able Note with a viewport. That they are Separators in Outline View should not prevent them or their children from showing in Map View. (My suggestion is to have some small visual indication in Map View that these container Notes are Separator Notes. That they are titled, and that they have children, is already immediately apparent in Map View.)
The problem we are looking at here arose (afaict) when Separators were accidentally allowed to have children. If they don’t have children, they should not show in Map View. A childless Separator is never a container — it is just a visual indicator. Interestingly, this is very much like Adornments in Map View (NB: afaik), which, it is carefully pointed out, are not containers and never show in Outline View. But since Separators can have children, they become containers. It makes sense to me that all containers should show as containers in Map View. The solution is to either not allow Separators to be containers (make them like Adornments), or to show Titled Separators with children as containers in Map View.