How to access Vertical Tabs from Contrib Modules in Panels? Drupal node forms have a vertical tabs area, which provides options such as "Revision Information", "Authoring Information", "Publishing Options" etc.
Contrib modules such as Node Hierarchy and XML sitemap can add custom tabs to this area.

How do you access these tabs from contrib modules in Panels. 

In the past, with Drupal 7 &amp; Panels, you could access them via the "Form" section of "Panels > Add Content".
However, I am creating a new Drupal 7 site and I can no longer access Vertical Tabs from Contrib modules. Only the tabs from Code Drupal modules are shown.

Steps I have tried to overcome the problem:

1) I have made a fresh install with just Panels and Node Hierarchy.
I have made a second fresh install with just Panels and Xml Sitemap.
In both cases, Vertical Tabs from Contrib modules are not accessible.

2) I have tried installing Node Vertical Tab Elements. It too only gives access to core tabs (and not tabs added by Contrib modules).

3) I have tried upgrading my older Drupal 7 sites to the latest versions of Drupal 7. In these older sites, the Vertical Tabs from Contrib modules are still accessible, so I am not sure if this means a special setting is required to access the tabs. I have disabled all custom themes and modules on the site, so I know the tabs are not coming from custom code.

Any help would be most appreciated.
Sounds like this should work.

In your 1) scenario, where you restricted your installation to the minimum amount of modules -- you might have run into a change/bug with a module version which you intentionaly have upgraded. Try not to test with "most recent versions".

Because you phrased your experience as "in the past you could ...".