copy and pasting a mail I sent to support (thread::9EI5a0wHCPm2fUuGVKPs3QM::) and they sugested tell it here.

"I continue to pay for and use Yahoo Mail Classic precisely because I rely on right-clicking to open messages in separate browser tabs; I read through them and close the tabs as I reply—or don't reply—to the emails. It’s simple and efficient, and it has been my way of using Yahoo Mail since the days when it offered only a few megabytes of storage.

Honestly, I’ve never understood the need to have everything contained within a single browser tab. It makes little sense—it’s actually kind of stupid, if I may be blunt. It strikes me as a design choice that isn't grounded in actual user habits.

I hope Yahoo reverses this change regarding how messages are handled, or at least doesn't force me to migrate to the "new" Yahoo Mail interface—as the banners appearing at the top of my inbox threaten to do.
If I wanted an email service packed with unnecessary features, bloated with JavaScript, AI, and other bells and whistles, I’d primarily use Gmail."