BUG: No message preview on folder change

["M . Thielker" <balsa t-data com>]

Hi,

 I've found another bug: when I close a mailbox, another one is selected, if
there are other mailboxes open. Within that mailbox there is a message
already selected from previous work. That message does not get displayed in
the preview pane, clicking it again also does not display it. I have to move
to another message, then back to get it to display properly.

This may also happen when manually changing folders and selecting one that
has been opened previosly.

Melanie