> You could create macros for hiding the next 5, 10, and 20
> directories. These could make it faster to hide lots of them.
>
> I wonder if it would be possible to write one to hide all
> subdirectories except particular ones marked in some way. ...
>
> Eg it could hide all but the tagged ones (dir mode) or all but the
> logged ones. ...
Speaking of Dir Mode, there's an Alt-Log command there, for Disk drives or 'Tagged directories'.
Try this: - sWitch - Showall - then Tag one or more directories, and then use Alt-Log, Tagged -- to see the options.
A new "Selective Branch Collapse" feature could be added there, by adding a 0-level (zero-level) option to the "Log Tagged", "1-9 Levels" -- in order to do a "Shift-Numpad-Minus"-type operation to Hide each directory that you have Tagged.
Bill