(Configured via Preferences / Folders / Folder Formats / Automatic Formats.)
Makes this aspect of Opus similar to File Explorer, with changes saved implicitly, and folders remembering how you left them.
When on, changes you make in a Lister that affect the Folder Format (view mode, columns, grouping, sorting, etc.) are automatically saved for the folder you are in.
When off, changes must be saved explicitly, as before. If you find automatic formats messy, you can simply turn them off.
You can freely mix automatic and explicit settings. If a path has an explicitly saved Folder Format, that will override any automatic one.
By default, automatic formats for up to 100 folders are remembered. You can change the limit in Preferences.
Automatic formats are kept in a separate list. Your curated Folder Format list won't be flooded with garbage!
You can view the list of paths that have an automatic format saved in Preferences. A button there can clear the list.
Right-clicking a path in the list gives options to forget it, or convert it to a permanent Folder Format.
Automatic formats, if on, alter the Folder Format rules slightly: Editing one folder and then changing to another will load the format for the new folder, rather than make the edit "sticky".