On 5/28/2025 7:46 AM, Stefan Monnier via Bug reports for GNU Emacs, the 
Swiss army knife of text editors wrote:
> Using the `rear-nonsticky` or `front-sticky` properties is a PITA with
> lots of odd corner cases, so I'd much rather we try to use the
> standard approach of removing all our properties at start.

Ok, I removed that. That means we don't need to add 
'append-text-property' just yet, though it would probably be a useful 
function to add one day.

I also wrote some tests for 'remove-display-text-property'. In the 
process of doing so, I found a nasty bug in the existing implementation 
(fixed in the first patch).