Thunderbird doesn't open file attachments with certain characters in the filename
 

This has been bothering me for years. From distribution to distribution and from version to version, it still remains.

If a client sends me an e-mail with a file attachment, it opens with a normal double-click as long as the filename has only characters like A-Z and 0-9, etc.

But when the attached filename contains one of the following characters, it won't open or Thunderbird messes up the characters while passing them as a parameter to OpenOffice.org, GIMP or Firefox for example, causing an error message in the associated program:

Problematic characters: ä, ö, ü

I can save the file manually and then open it from Konqueror without issues. But what can I do to make it work with a double-click from Thunderbird? This is what I've tried in the several years struggling with this:

- tried various encodings (including UTF-8) for the filesystem of the tmp-folder, where Thunderbird saves the attachment temporarily, passed the encoding as an option in /etc/fstab
- tried to export various encodings (including UTF-8) before running Thunderbird
- went through every single Thunderbird setting to find the settings for message encoding, nothing seems to help

Is it even an encoding issue? What could I still try?