I just tried your steps with Shotwell 0.11+trunk, Ubuntu 11.10 and Thunderbird 7.0 and everything worked just fine - both the on-disk filename and the attachment filename contain spaces. So it looks like this has been fixed by the newer versions of one or more of these software entities.
Andries,
I just tried your steps with Shotwell 0.11+trunk, Ubuntu 11.10 and Thunderbird 7.0 and everything worked just fine - both the on-disk filename and the attachment filename contain spaces. So it looks like this has been fixed by the newer versions of one or more of these software entities.