Hello,
I noticed that after last update, after i login in Virtualmin the Virtualmin Refresh button is missing on System Information.
Also, when uploading file thru File Manager the background stay dark and i must manually to refresh the browser.
Me too! 
Hi,
This may be an issue introduced in the Authentic Theme, or an intentional change.
Visit:
Search to see if someone has reported this, and post your feedback, or open a new issue so it can be looked into.
I think it is because it is no longer needed since much of it updates in realtime.
File Manager: Post upload unresponsive UI #903