Mutt's current behavior is consistent with elm and other mailers.
This is traditional mbox behavior. I happen to like it.
> Great! Developers, will you change it then? :-)
I hope not. There is no need to have the mtime to be updated
every time the ctime is updated. (Or, if there is such a need,
maybe make a new variable "touch_folder_upon_delete" or something,
with a default of "no".)
If you have a tool that really needs to see if a file has been altered,
it merely needs to look at the ctime rather than the mtime.
This is safest behavior, since user programs *can't* set ctime
by themselves. (You can check ctime with "ls -lc".)
Backups and similar programs already need to look at the ctime
rather than the mtime anyway, in order to pick up files that
have been renamed or moved.
Cheers,
Stan