bug#3003: 23.0.92; Point trapped in overlay

[Stefan Monnier]

> Stefan, this is due to your change.  Here is an easier recipe to
> reproduce the bug:

Yes, I recognized it right away :-(
I think we're just going to have to revert that change for now.

Tho, I think that in reality the "right" fix is to only place the
rear-nonsticky property on the last invisible char since inserting text
in the middle of the invisible "http://www.google.com"; shouldn't result
in an invisible "http://www.go"; followed by the visible inserted text
and then an invisible "ogle.com".

Or maybe the invisible text should be marked `read-only' and then my
code could be changed to only kick in for writable text.  But this would
require more changes to the handling of read-only (currently read-only
text is usually unbearable because it can't be removed, whereas what is
usually intended is just "don't modify, tho feel free to remove it
altogether").


        Stefan