Attach files to Webpage leads to a dead end

[Sebastian.Drude@gmail.com]

I want to attach a PDF file to a webpage.
But I cannot access the file either by uploading nor by searching a previously uploaded file in my library of files.
Steps:
1) Edit basic regular webpage
2) Press "Add media"
3) Upload the file
4) I end up in a inner window of the media browser where the uploaded file is shown; but there is no way to indicate that this file needs to be attached. If I close the inner window, no file is attached.
5) instead of uploading, I try to search for the files in "my files"; but the file in question does not show, although I find it if I go directly to "my content -> my files"

See screenshots attached.

[Sebastian.Drude@gmail.com]

screenshots that illustrate what I write

[André Moreira]

I was able to do it on the dev website. See ​https://dev-www.clarin.eu/content/test
Can you please try your case in some page in ​https://dev-www.clarin.eu?

What I did:

1. Go to: ​https://dev-www.clarin.eu/content/test
2. Click "edit"
3. Click "Attach media" -> "Browse" button
4. Click "add files"
5. Double click the file I want to attach
6. Click "Start upload"
7. Click "Next"
8. Click "save"
9. After clicking "save" the inner window is taken to a render of the attachment page. Don't bother with this, just close the inner window using the "x" on its top right corner.
10. Click "Attach media" -> "Browse" button (again)
11. Select the tab "My files" inside the inner window
12. Select the file you just uploaded (should be visible now)
13. Click "Submit" (the inner window closes by itself)
14. Click "Save" to save the page you are editing