(1) When I hit [option][command][1] to create a title, I should be able to enter “>> My Header Text” and that should make header collapsible.
(2) Hitting Enter at the end of Collapsible header, the newly created line should be collapsible by default.
(3) When the cursor is on a collapsible line and I hit [option][command][1] to turn it into a header, it should remain collapsible. Right now it requires an extra step.
… etc, you get the idea.