Adding sys_pubdate to display format

Hi!
We need to add the Item Publish Date column in the Display Format of Content Explorer for the user. But it seems that the System field sys_pubdate is not showing up in the Add Column(s) field selection of the Display Format Editor. Did I misss anything? Or is this a known issue of workbench?

Thanks for your help!
Andy

Optional system fields will not be available for adding to a display format until the field is used in at least one editor. If a display format has been opened in the workbench before this was done, the workbench needs to be restarted to pick up the change because it caches the field list.

Thanks much! Paul.
It did work!
But now it seems that the Pub Date field in Content Explorer Display Format is always blank regardless the items had been published.
Do I need to work on something else to make the Pub Date show up?

Thanks!
Andy

http://forum.percussion.com/showthread.php?1234-sys_pubdate-and-sys_contentstartdate&highlight=sys_pubdate

“Will be fixed in a later release”. Just to clarify, this is broken in 6.7 but I believe it had worked in 6.52.