modify PcManFM in debian Lxde
Posted: Fri Oct 16, 2020 9:42 am
how do i modify the pcmanfm menu to have the right click option mount the read-only usb device? 
You want "Actions".
See here: http://lxlinux.com/#2 - scroll down to "Pcmanfm Actions Menu".
The article is a bit dated, but I know that actions work. Let us know how it goes for you.