I'm trying to create a plugin that alters the Add New Post page so the Visibility field says "Private" by default:
Status: Draft Visibility: **Private** Publish immediately [Publish]
...as opposed to what WordPress normally assumes:
Status: Draft Visibility: **Public** Publish immediately [Publish]
At the moment, I'm using the "wp_insert_post_data" filter, and that is allowing me to change any posts with a post_status of "auto-draft" to "private". While this works, there is an unintended side-effect: Changing the post_status to "private" seems to publish the post automatically, changing the button in the editor to "Update". Furthermore, if the user saves before specifying a title, the post will be published with the title "Auto-Draft".
Is there any way I can simply change Visibility to Private by the default, in a manner that doesn't auto-publish the post, and change the button to "Update"? In vanilla WordPress, users can manually change the visibility to Private, and the button remains as Publish... I just need to achieve that via a plugin. I also want to ensure that "public" can still be selected by the user, should they desire to.