Comment 9 for bug 802964

By valid .desktop I meant for trash (gnome-open
It's needing this type of mimetype= line in nautilus.desktop

MimeType=x-directory/gnome-default-handler;x-directory/normal;inode/directory;application/x-gnome-saved-search;

doesn't resolve fact it will get bumped from the front of the added associations line, but users can put back easily, though added associations should be appended, not added to the front