In legacy exact-name mode the name field wrote the filename prefix as
well as the exact name, so clearing the field to return to composed
names left the original prefix gone. The field now writes only the
widget it shows.
A second Browse left the first popup's outside-click listener behind,
which closed the new popup on the first click inside it. Each popup now
owns its listeners, Browse toggles it, and Esc closes it.
Embed workflow is an off | embed pill like every other boolean on the
pack's cards, instead of a small switch.