"Put New Keywords Inside This Keyword" was a session preference that
followed renames by hand: undo and redo never moved it back, so after
undoing a rename it named a keyword that no longer existed and the
next new keyword silently made that parent again. It is now a mark on
the keyword in the catalog's keyword list (`new_keywords_inside`, one
keyword at most): it moves with its keyword (into a merge too), goes
with it, comes back with undo and redo, and is kept with the library.
Setting it is one undo step.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>