[Users] How claws mail treats and deals with new and unread messages?

[Brian A]

CM is working correctly with IMAP for new, read, and delete.  I can
verify that because I use a Yahoo account with IMAP. Claws mail acts
exactly as Paul has stated.  If I don't have CM open and use the Yahoo
webmail interface,look at a new message, it is marked read.  If I then
open CM and look at my messages CM will know the message was previously
read and not show it as new. If I'm only using CM and read the
messages, then open the webmail it will show them messages which I've
looked at as read.  If both webmail interface and CM are open at
the same time, and one message is read in webmail or CM and then look at
the other client, a refresh is required to get the status from the IMAP
server.  This should be expected, that the status of a message is only
refreshed when the server is queried.  The RFC does NOT call for the
server to push message status to the client.

But let's look at your issue from a different lens. 
It is totally unclear why you would leave a security issue, leaving
your workstation open in TB at work.. Most security conscious
corporations would look at that situation and see a reason for
termination.  Good security practices indicate that any time a employee
is not monitoring their workstation that their account should be locked.
Secondly, has the corporation's security team given permission to
access the corporate asset with CM?  While CM is an open source and reliable
client you are open to a liability issue if it corrupts a corporate
assett, i.e. the emails sent to your corporate account are the
corporations not yours.

Additionally, I believe you are misinterpreting the problem by focusing
on CM as the cause of your issue.  Either you are expecting IMAP to act
in a different way than it is designed, or TB is doing something, or
you are failing to "refresh" the query status of emails. Do you have TB
running any scripts when a new message arrives? Are there scripts
running in either client that handle the message?  If this is a
corporate support account, where you need to use the corporate
approved TB even at home? Do you know that someone at work isn't
reading the message with TB open on your work desktop? What are the
settings in TB, does it mark all messages read after a certain amount
of time? Is this a shared account with other users accessing the same
mailbox and they need to be taught to leave a message marked unread
until it is handled (CM can support not marking a message read)? You
might be using the wrong work flow method and trying to force the mail
clients to follow a work flow IMAP isn't designed to follow.  

I really think  you need to give some thought to why you are leaving an
account open at work, why you are using two different clients, and
why your work flow is to have two clients looking at the same
account. If nothing else try TB at work and TB at home to see if the
results are different.

Otherwise more information is really needed to help you select the
right solution for you desired work flow.