Version: (using KDE KDE 3.1.94) Installed from: Debian testing/unstable Packages originally from: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=224917 --snip-- It seems that if you paste text which has a new-line into the subject field of a message kmail will include a new-line in the subject! The following URL has an example of such a message: http://lists.debian.org/debian-isp/2003/debian-isp-200312/msg00180.html To create such a message just copy two lines of text (two lines from a Konsole will do) and paste it into the subject field. You will notice that the title bar gets screwed up, and the message will be too if sent in that manner. --snip-- I managed to repeat this once using kde 3.2RC1 and kmail 1.6, using the middle-mouse-button paste. most time mmb and shift-ins seem to work fine.
The example was created with KMail 1.5.4. The current version of KMail correctly encodes the newline character. Nothing in the standards forbids a newline character in the Subject provided it's encoded correctly.