Postfix mail queue function "hold selected" not working

I need to clear out some old "stuck" messages, and attempted to put those on hold by

  1. going to: Webmin > Postfix Mail Server > Mail Queue
  2. clicking on "select all" to select all messages on page
  3. clicking on "Hold Selected" to hold those messages

Expected to see "held" or something similar in status column

Status column does not change and all messages shown before still show.

Status: 
Active

Comments

Putting a message on hold doesn't flush it from the queue though ..

Also, the postfix mailq command that Webmin uses to query the queue unfortunately doesn't show the message status.