How to download persistent.parm file from cube orange using MavFTP in mission planner

Hi, how to do MAVFTP with mission planner?
I want to download the file @SYS/persistent.parm but I am unable to.

I am connecting the cube with usb and opening the mission planner, then i go to config and MAVFTP and i click on the @SYS, I am able to see the file list, and persistent.parm file is there but when I click or double click on that file nothing happens.

I want to know how to simply read or download this file. I am using Quadplane 4.3.0 with stable mission planner build of 1.3.76

Thanks in advance!