Each folder window has the same column bars: from, subject, date/time, size.
Also the assigned "Copy to Self" folder has these predefined columns, but when a sent mail is being copied into it, the "from" column contains entries like: "To: addressee". This might be accepted when working only with Pmail.

But when using different mail clients (e.g. Thunderbird) to access one mailbox, these other clients always enter the real sender address, means my own address, into this column. And that is correct behaviour since the column is named "From".

"Copy to self" folders should get a real column "To" instead of abused column "From".

So you are complaining about the "misleading" label of the column which only shows addresses starting with "To:" so you might erroneously misinterpret them as being "From:" addresses because other email clients don't do so, do I get this right, Joerg? ;-)

Well, I'm using a pair of folders in a tray fo each recipient I'm reading/writing more than a couple of times with and guess what: There's one for the incoming and one for the outgoing messages so I don't mix them up. This isn't a joke and I'm doing so ever since I started using email at all. IOW: Column headers don't matter to me plus it takes double the time to hit the 2 GB folder size limit, pretty convenient!

But although I'm not quite sure, it might become possible to better customize folders in Pegasus Mail v5.

Maybe I should explain a little bit more detailed what I mean.
We are living in times where mailboxes being accessed by different mail clients, think about smartphones, home office workers, etc.
Also with us, our mailboxes, hosted by Mercury at a local server, are being accessed by Pegasus, Thunderbird and Roundcube.

When you are sending a mail by Pmail, it is making a "copy to self" entry into a folder of your choice (if configured), e.g. "Outgoing 2022". But this folder has the same column headers like incoming folders. Additionally these columns cannot be adapted. That's why Pmail is using a "workaround" and is adding "To:" entries into the "From:" column.
This is not a problem as long as you are only using Pmail and it doesn't matter to me whether the column header reads "From" or "To" as long as within the column each outgoing mail is marked with "To: addressee".

But when sending mails (from the same mailbox account) using Thunderbird, it is adding the real sender address (my sender address) for "from:" entries, which is correct.
But if you later using Pmail again, the following is shown in your "Outgoing 2022" folder:

You see that mails which has been sent by Pmail are marked with "To: addressee" entries while mail which has been sent by Thunderbird are showing my sender address only, which is normally correct for a "From:" column.

Pmail should have configurable columns like other mail clients have. Then the user could select what kind of columns he wants to see. Then he could chose a "from" column for incoming mail folders and a "To" column for outgoing mail folders, or of course both, if you want to see the "from" and "to" entries. See below the column header context dropdown box of Thunderbird, where you could select which columns should be shown.

OK, for now there's only a work-around: Highlight these messages and select Message properties from the context menu (or press F12), then enable the Is a copy to self flag from the list of properties and press the Return key as often as the dialog pops up. This will change the display of all messages previously selected to the same way as Pegasus Mail does by default.
I don't remember whether there's an extension available for achiving this via a filter rule but maybe someone else of the long standing Pegasus Mail users does. It shouldn't be to difficult to create one, though ...

Ah yes, I see, that's different from my concept because I'm using normal folders for outgoing messages as well, not a special "copy-to-self" folder for all outgoing messages (which IMO doesn't make any sense unless sorting by tasks instead of recipients since you can only have a single "copy-to-self" folder).

Moin Michael,
Background is the data protection requirement to delete all mails which are older than 10 years. And I'm the data protection officer in our company and responsible that all personal data being deleted when the legal data retention time has been exceeded or the reason for processing of personal data is gone.
And that's why our staff should sort its mails into annual folders, divided by incoming and outgoing mail. That makes it easier for me to delete the obsolete yearly folders for my 20 users since nobody else takes care.
But of course, for special projects we are maintaining also other folders with mixed incoming and outgoing mail conversations.

Refer also to this forums thread, which addresses the problem as well:

how-can-i-change-column-header-panels-in-sent-folder