How to prevent message list from scrolling to the top when using Horizontal Preview?

How to prevent message list from scrolling to the top when using Horizontal Preview?

I use Zoho Email in my web browser with my monitor in portrait orientation. I have therefore selected "Horizontal preview" so the message preview appears at the bottom of the screen.

However, each time I click a message to read it in the preview, the message list automatically scrolls to place the previewed message at the top of the list. This is very confusing, disorienting, and serves only to hide new incoming messages until I remember to scroll up again.

I do not see this strange behavior on a landscape monitor using "Vertical preview" (where the preview appears to the right); in that case, the messages in the list stay as I have scrolled them.

Please can you make "Horizontal preview" stop automatically scrolling the message list (or at least add an option to prevent this)?