Autocomplete throbber is visible when entering a blacklist character

This should address the bug. I wanted to add tests for this in core/tests/Drupal/Nightwatch/Tests/claroAutocompleteTest.js but I couldn't get Nightwatch working locally 😬

Got my Nightwatch setup working 👍 Here's test coverage and an updated fix.

Maybe I'm missing a step but applying the patch

Added an entity reference field to the Article content type
Typed '/' and I see the throbber and "loading" flash very quickly.

Shouldn't I not see that?

The bug is specific to the link autocomplete which is supposed to have the autocomplete disabled when the string starts with a character from the ignore list /#?. You can test this by adding a link to a menu.

Forgot to add my tag earlier.

Tested on a menu link and now see what you are referring to.
Patch solved the issue.

Side note. Should publish an article on setting up nightwatch. Still can't really get it working on ddev.

Manually tested and looked over the code. The issue is specific to Claro (and likely evaded tests) as it is due to an 'autocompletesearch' event listener that adds the class on any attempted search, even if it begins with a character that results in the search ultimately not happening. Solution looks simple enough and the failing test proves it was a problem. Nice fix!

Committed to 11.x and cherry-picked to 10.1.x since it's a not-particularly-disruptive bugfix.

Automatically closed - issue fixed for 2 weeks with no activity.