If user has access to only one project, they cannot filter by custom fields

I have some users who have access to only one project. When creating a (new) search filter, there is no dropdown to select the project (see JRA-8351), which is fine. But then it probably also doesn't trigger the logic to display custom fields based on that project. So the only custom field I see is "Participants" from the toolkit. And there is no way to filter on any of the other custom fields, even though they can certainly see them in the issue. I did find a workaround though... if I edit an existing filter, the custom fields do show up because it already knows the project. But they really should show up first time.