shadowsock server, not using dnscrypt server

[jojothehumanmonkey]

hello and thanks,

my opnsense router is running dnscrypt and that is working well.
also, i have installed the shadowsocks server.

on my computer, on the lan from that opnsense router.
i am running a shadowsocks client.

using ms-edge, not using that shadowsocks clients, dnsleaktest results look very good.

using my main browser, firefox, pointing to that shadowsocks client, internet is working.

using firefox, having ENABLED "Proxy DNS when using SOCKS v5"
i do a dnsleaktest, the results are not good, pointing to my isp dns, verizon.

using firefox, having DISABLED "Proxy DNS when using SOCKS v5"
i do a dnsleaktest, the results are good, clearly using the dnscrypt


so why using shadowsocks, the dns is not using dnscrypt server?

thanks,
david