In JENKINS-42123, some button styles were added to show that a form submission is in-progress or succeeded. (Error state was also supported, but not actually displayed in the UI, as the existing form validation error messaging was deemed sufficient feedback).

A reusable button control was created to accomplish this but it may not be ideal from an API / coupling perspective (see discussion here: https://github.com/jenkinsci/blueocean-plugin/pull/912)

Once a few more concrete use cases are established, we should try to make supporting these kinds of behaviors as easy as possible so that we have consistent UX and components that are easily transferrable to other teams.