[bug?] When creating event, a click on tag field should display a list of available tags

When creating event, a click on tag field should display a list of available tags, but it doesn't. It does somehow "activate" and start showing some tags when you start typing characters that match though, and, if you delete those characters, then, as it is "activated", shows the whole list of tags.

using version 1.16.2~ynh2