[reemas]

sometimes when i click on an email in mac mail, it highlights in light blue other emails. it seems pretty random anyone know why it does this? thanks!

[wataru]

It's not random. The highlighted messages are ones that Mail thinks are related to the one you clicked on. You can turn it off in the "Viewing" section of Mail's preferences, but I find it convenient. You can also have it group those mails together in threads by choosing the appropriate option in the View menu.

[CatOne]

Originally posted by reemas:
sometimes when i click on an email in mac mail, it highlights in light blue other emails. it seems pretty random anyone know why it does this? thanks!

Those are other messages in the same thread (i.e. they're replies to each other).

You can also collapse all those messages into the same thread, which groups things logically and can reduce clutter. Just select "view->organize by thread".

There's a bug right now where if you have some mailboxes organized by thread, and others that are NOT organized by thread, and you switch back and forth between them, the columns get a little janky (that is, they detach themselves and resize). Annoying (to me, at least).