After trying to send a mail, I wanted to inspect my Local Folders/outbox. It showed two unread mails in the collapsed tree view, but "No messages in this folder" in the list view. The maintenance view shows the two mails correctly. Seen in version 4:4.6~20101025.1189387-1maemo1.1188357 .
After an update and restart, outbox content is now properly displayed.
In version 4:4.6~20101025.1189387-1maemo1.1188357 I cannot reproduce the problem. Test: 1. Try to send two mails. 2. Look at the Local folders/outbox => 2 Unread , both mails are displayed.