Version: (using KDE 4.4.2) Installed from: Ubuntu Packages The short mail header (view->header->short) in the message view should get a "details" link. Currently it displays the most important data, including "from". This is not useful for a mailbox storing "sent" emails. In that case a "details" hyperlink/button would be helpful, that expands the short header to something more similar to the "standard" mail header (which in turn is lacking the time/date of the message and thus is not ideal either).
Thank you for your feature request. Kmail1 is currently unmaintained so we are closing all wishes. Please feel free to reopen a feature request for Kmail2 if it has not already been implemented. Thank you for your understanding.