Enabling #enable-experimental-web-platform-features in Chromium breaks custom queries

[westonruter]

With the #enable-experimental-web-platform-features flag enabled in Chromium (both Chrome and Edge), attempting to do create a Custom Query (such as by Summary, Description, or Reporter) results in an error in the console:

Form submission failed, as the <SELECT> element named '0_description_mode' was implicitly closed by reaching the end of the file. Please add an explicit end tag ('</SELECT>')

This was also reported ​upstream to Trac directly 5 years ago, but closed as a Chrome-specific bug. Nevertheless, it seems this might not be the case as the ​Chromium ticket was closed as wontfix.

I was able to fix the problem locally via ​Local Overrides in Chrome DevTools. I modified ​https://s.w.org/style/trac/common/js/query.js?v=216 by simply supplying the missing </select>:

44c44
<     var e = $($.htmlFormat('<select name="$1">', name));
---
>     var e = $($.htmlFormat('<select name="$1"></select>', name));

[dd32]

If it's not a Trac bug, and it's not a Chromium bug, it must be a jQuery bug, right? :)

(I think it's a Chromium bug; too many JS libraries exist that wouldn't explicitly close a HTML tag)

I'm not overly interested in fixing this on the WordPress trac instance, as it'll require either monkey patching the Trac JS, or making alterations to it.

The Trac CSS & JS needs upgrading though, so perhaps we can look at making the change..