I see this thread was last active long ago, in 2021. I see a somewhat related thread, Show folder name in conversation view and a couple other threads that could be summarized as, “Do conversations the way Outlook and PostBox do it.”
I think I can provide a simple example of the problem:
eM Client puts all messages in all folders into a conversation.
Thunderbird, and PostBox puts messages in a PARTICULAR folder into a conversation.
Here is my use case:
I BCC myself on every email I send. This is a habit I got into when email was young, and one that when I stop doing, bites me when some new email client or email infrastructure misbehaves.
This means that EVERY conversation that I participate in shows TWO messages from me every time I reply: One in the folder where I’m managing the conversation, and one from my BCC’d SENT folder.
Here is why the eM Client conversation implementation that puts items from ALL folders into a conversation is bad for me, and is a “deal breaker”. I probably will NOT switch from PostBox to eM Client because of this:
When I am through with a conversation, I delete the whole conversation.
However, as a backup, I do NOT want the Blind Carbon Copy in my SENT folder to be deleted. OOPS! eM Client has an interface that is confusing and destroys data with this setup. I see 2 copies of everything I sent, and my SENT copy gets deleted when I delete the conversation.
If eM Client has no way to say, “Keep messages ONLY in this folder in the conversation.” And “DO NOT include items in my SENT folder in my INBOX or other Folder conversations”, then I cannot use it.