active autocomplete widget is not shown

When an autocomplete field is inactive, it shows a grey circle at the right of the text box. When you start typing, it's mean to change into a blue spinning circle, to show the user that something is happening.

To reproduce:

1. look at an autocomplete field, eg, the 'parent issue' field here.
2. notice the autocomplete spinner is inactive and grey
3. type in or paste a value
4. the spinner vanishes while the browser fetches results. It should show the active version of the spinner.

Major because there's absolutely no feedback for the AJAX query action, and unless you know how Drupal works and you've spotted the inactive spinner and you know what it means, you've no idea you should wait for the lookup to work.