Outlook does not delete but displays deleted messages as strike-trough

[Thomas Schlosser]

Hi,
unfortunately I have some Outlook-users on my IMAP server.
When a Thunderbird user deletes a message, it vanishes from the mailbox and moves into the "Deleted
Items" box. From an Outlook client the same deletion does not delete the message but displays it in
strike through letters - the message can still be opened.

Does anybody know the reason? Can I change this behaviour either on the client or the server side?

Thx in advance
Thomas