There is a big need for a state-ful GUI markup standard, for both desktops and http apps, as HTML/CSS/DOM has many gaps and problems (see link), and reinventing them via JS/HTML/CSS/DOM has proven to be a chaos party.

However, I didn't find XUL very intuitive. For one, it seemed verbose for common stuff. If there were a rhyme and reason behind its oddball approach, it never clicked with me.

https://www.reddit.com/r/CRUDology/comments/10ze9hu/missing_...