It couldn't. When you click on edit button it scrolls you down to reply form and adds the content of the post you want to edit.  All works fine.

"adds the content of the post you want to edit"

But I don't want to add, I want to edit.

Rick

When I say "adds a content" i mean it brings and put the content in the editor to allow you edit and save. Just edit the content and click on save button.