Probem sending email with thunderbird with documents that have greek characters

When I hit the send email button from libreoffice it opens a new mail window in Thunderbird and it puts the filename in the subject field.

The problem is that if the filename is in Greek, it does not show the Greek characters, it puts English question-marks in their place.

Example.

If the filename is ΑΒΓΔ.xls , it makes it ????.xls.

I know that the problem is not from Thunderbird because if I do the same using Microsoft Office, the problem does not occur.

I am using latest versions of Libreoffice and Thunderbird. In the past it worked correctly but after a version of libreoffice (I don’t remember which one, maybe since version 4) I started having this problem.