Just though of how to make the work easier for me. I guess it turns out to be useful for others, thanks for the good words.
QUOTE(Deulkkae @ May 19 2021, 18:21)

I don't know much about scripts, is there any way I can keep the box opened by default?
This is quite hacky but probably also the cleanest way to go about keeping it open. Change to the from:
CODE
div.addEventListener('click', makeTdnList);
})();
// useful to tell us if something blew up
console.log('eh-maketdn is active');
to
CODE
div.addEventListener('click', makeTdnList);
div.click();
})();
// useful to tell us if something blew up
console.log('eh-maketdn is active');
(i.e. add div.click(); to simulate a click)
I will add some memory of whether things are in open or hidden state as a requested feature. I guess some memory will not complicate things too much but I need to do some heavy testing for some edge conditions in such a case. e.g. leave it hidden in one gallery, open another and unhide, go back to the original gallery and unhide there too.