Version:           1.13.1 (using 4.4.1 (KDE 4.4.1), Kubuntu packages)
Compiler:          cc
OS:                Linux (i686) release 2.6.31-19-generic

When deleting an attachment from an email within a folder (sent or received, but not during message composition), kmail jumps to the next message down in the list. If you have multiple attachments to delete, this means having to re-select the message.

If you open the message in its own window, rather than doing it from the preview pane, the message window stays on the correct message, but the selected message in the list pane still jumps. If you try to delete a second attachment from the first message (via the window), it will not actually be deleted.

Additionally, there is no feedback in the message window (unlike the preview pane) that anything has been deleted, even when it has. You will need to re-open the message window to see the change.