Add message next to POST button when something in missing in the post

Sometimes when writting a contribution people don't follow exactly the order of form in the page to create it. A user could first write the content, then the title... or the title, then the tags... however.

The problem is that maybe someone could press the POST button and it seems like it doesn't work but what is actually happening is that one text-box hasn't been filled. It could be the repository, the tags, or the title itself.

Actually the error messages look and appear like this:

Suggestion

To add a message next to the POST button to let users know what they are missing in the form. So no one gets to think it is not working for a while before they scroll to realize they missed to fill something:

_{Cover image from pixabay edited by me.}