whatwg
Don't force <details> to be a block.
What is the issue with the HTML Standard?
https://html.spec.whatwg.org/multipage/rendering.html#the-details-and-summary-elements says:
This effectively ignores display set on the details element, so if you want to set display: flex, for example, you're out of luck.
This bites authors, even very experienced ones. The last one I'm aware of in bug 1856374.
There's no particular reason that this has to be the case. Probably it had to be the case before <details> was specified in terms of Shadow DOM, but now I'm not aware of any reason for this.
This was discussed in the CSSWG when @dbaron brought up https://github.com/dbaron/details-styling. He probably has a bunch more context on this stuff, but I think lifting this restriction should be uncontroversially better, if we can get away with it.
I am interested in working on fixing this, as discussed in the CSS WG meeting in July -- as part of trying to make the details element more styleable. I've prototyped this change and some other changes in Chromium in https://crbug.com/1469418 , but with the intent of experimenting with what I prototyped and likely making major changes. I got a bunch of feedback from @bramus who tried to use the prototype to build a bunch of things with it, and I'm part of the way done going through that feedback (but currently sidetracked to get some other things done). Once I do that, I need to (possibly not in this order) write some major updates to https://github.com/dbaron/details-styling to reflect what it is that I've prototyped, probably try to get another round of feedback from @bramus and hopefully build a few more demos, and start making some more concrete proposals for what to change in some combination of the Open UI CG / the CSS WG / the HTML spec. I'm hoping to get back to working on that sometime later this month.
Here's an example of something I just tried to do and failed due to this (surprising) property: https://developer.mozilla.org/en-US/play?id=qbeKgiwJ2WxDjsbUmJNfYhVslwx4xw4CMyqPgebp2%2BICmuMP9DjzHQ0UcN344sA34UImTFR%2Bhg9YsIYY It would make me happy if @dbaron was able to fix this.
I'd like to slightly broaden this issue to cover both the <details> and <summary> elements. In at least Chromium and WebKit the <summary> element also has restrictions on its display type; I've prototyped removing both sets of restrictions behind a flag, as noted above.
I need to do some further investigation on whether those restrictions are supported by statements in the HTML spec... but if they are I'd like to remove such statements along with the statements restricting <details>.