Email body truncated at 255 bytes

[andrea.ippo]

Reproducible: always

Steps to reproduce:
1) right click an image file/a set of image files, right click it/them, select "Send by E-mail".
2) compose an e-mail body that is longer than 255 bytes/characters, e.g. copy and paste the "0123456789" sequence various times (at least 26). Be sure you end the e-mail body with a complete 0-9 sequence, this will help later
3) provide other information, such as recipient address and subject
4) confirm

Expected results:
your default e-mail client opens and you have the message you expect: same recipient, subject and body, with the selected image files as attachments

Actual results:
your default e-mail client opens, but the e-mail body ends with a partial "01234" sequence, that proves that the body gets truncated