Automatic Creation of Mail Chains - WHY?

Why does eM Client merge all e-mails (no matter how old) into one chain if the Subject line already exists? Unless there is a setting to stop this from happening automatically, this make eM Client almost worthless. I can’t figure out how to stop this. Yesterday, for example, I received a single forwarded e-mail and it now exists in one e-mail along with more than 20 others, some almost 4 years old. If I want to delete any of the 20+ e-mails, all of them are deleted.

If there is no way to stop this in the free version but can be done in the Pro version, I will happily upgrade.

Is anyone out there who can explain this to me?

Settings > Mail > Read > Conversations > Disable conversations