bug#15796: 24.3.50; rectangle-mark: Display issues in presence of TABs

[Jambunathan K]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> If the display engine offered a way to overlay (rather than insert)
> glyphs/graphics, we would have more options.

I thought that this facility already existed.  (I had a vague impression
that the `compose-region' and `reference-point-alist' helped one overlay
one glyph over the other)

Thanks for the note.

I am happy with the current state of affairs.  It is an improvement
already.