The "edit button" may do a "search / replace" if the "OK" is clicked.
eg:
\customize @due-date _type=date _mode=inline _endString="\" "
IMO @due-date:"21 May. 2021" may be an INLINE rule.
\customize @comment _type=text _mode=block _endString="---"
@comment There may be a multiline text
That can be edited in edit-mode.
It will be saved on tiddler save
---
The comment-field will be "protected" ... If the edit button is clicked, it will open a new multiline text area.
If OK is clicked, the text in the wikitext area will be replaced!
So there is only 1 source of truth. The wikitext.
PROBLEMS
{{!!comment}} doesn't work out of the box. ... except if the text is moved from wikitext to field .. on save
It would be interesting, to explore "wikitext dynamic fields"
See this post about "protected fields" : https://groups.google.com/g/tiddlywiki/c/AEvEPZaduHE/m/tdnbpaPlAAAJ
The "edit button" may do a "search / replace" if the "OK" is clicked.
eg:
The comment-field will be "protected" ... If the edit button is clicked, it will open a new multiline text area. If OK is clicked, the text in the wikitext area will be replaced!
So there is only 1 source of truth. The wikitext.
PROBLEMS
{{!!comment}}doesn't work out of the box. ... except if the text is moved from wikitext to field .. on save[get[comment]]won't work out of the box ...So may be there needs to be better tooling. !!