It’s impossible to attach PDFs already existing in the media library

Hi I found two problems in this plugin:
1 – When I upload a new attachment to download, the plugin automatically inserts the link also in the post, just before the text, so you need to delete it manually.
2 – It is not possible to attach in a post PDFs that are already in the media library. If I try to select them, the plugin only inserts the link in the text field but doesn’t add the attachment to the list.
Is there a solution? Thanks