Version: (using KDE 4.1.1) OS: Linux Installed from: I Don't Know I was currently testing an email account I added, sending a test message. I entered correct email address, and subject. When I tabbed from subject to start typing in the body the window itself and kmail froze.
If you start Kmail from a shell, do you see some debug messages? (I cannot reproduce using current SVN revision)
Can not reproduce on 1.11.2. Please feel free to reopen if you can still reproduce.