bug#41097: 28.0.50; (dired-toggle-marks) not working after copy

[Drew Adams]

> > > Thanks, I installed this on the release branch.
> > > OK to close the bug now?
> >
> > That "fix" is a real step backward, not forward.
> 
> I disagree.

Please reconsider.

Can you point to any other occurrence of referring
to some mark other than `D' as a "flag" - anywhere
in the Dired doc or code?  All marks, including
`D', are marks.  Only `D' is called "flag".