Selecting heading(s) and associated body text in the document window, copying them to clipboard, and pasting them to a new file, is a way to gather several headings and their text in a single document.
Headings have to be selected by hand in the Control Board, though.
Instead, it would be nice to search and select all headings that contain a certain word or symbol as a tag (*). Gathering those tagged headings and their text would then be similar to what Scrivener calls Collections, a useful way to track threads within a document.
Maybe there is a way to do that now?
(*) It's possible using Find, format Style and Select All in the document window, but of course the body texts are not selected. Having a way to select those found headings in the Control Board would do the trick.