ACF seems to freeze when a command takes a long time to complete
When using ACF to install a package (or other action that takes a long time to complete) the web interface freezes until it completes. This means the user is likely to think it’s broken and refresh or browse to another page. It would be good to have a standard feature that spawns another process (or thread) and uses AJAX to show status. ACF uses AJAX in several areas, so the new feature here is the ability to have an action kick off a separate process and return before the action is complete.
(from redmine: issue id 638, created on 2011-05-10, closed on 2016-05-31)