Wordpress 'add_action' content to 'postbox-container-1' in admin section


Staff member
I would like to be able to add a new 'widget' to the sidebar of the admin section, specifically on the "New Page" and "Edit Page" pages.

I am going through the Wordpress API Documentation, but I can't seem to find where to add a new section in the first "postbox-container-1" section.

If you go into a wordpress admin section, then click add page, I would like to add a new widget under "Publish/Page Attributes/Featured Image" widgets.

The closest I have come is this:
add_action('dbx_post_sidebar', 'pluginFunctionHere');
. Unfortunately, this adds all of my content under the main page WYSIWYG editor.

I know how to add it regularly, but I would like to make this a plugin for general use. Any ideas? or is there a specific hook for this section?