post_id missing from the wp-admin file upload request

I’m trying to upload an attachment using the “Add Media” button placed right above the editor. The request goes to the wp-admin/async-upload.php file. I can put a var_dump($_REQUEST); call there. Whenever I upload an attachment for a regular post, the $_REQUEST contains the post_id key and the attachment has that post saved as it’s parent_post. … Read more