Mail App On Macbook Pro

I have a 2 year old Macbook Pro running on Ventura 13.1. Within the MAIL App on the Mac, when I want to view a message, I must double click the message to open it. So annoying.

I just bought a Macbook Air, running Ventura 13.1 and the Mail App does NOT require a double click to open a message. A single click will suffice. Any ideas on how to change to a single click when using the Macbook Pro to open a mail message? Thanks for any help!

FYI...

I checked the settings and they are identical on both Macs as far as Settings, Trackpad, Tracking Speed and Click.