system extension in forwarding only shows parking and conference

[sigmaIT]

According to the documentation https://www.3cx.com/user-manual/call-forwarding/
System extension - forwards calls to a queue or ring group.
I cant enter an extension manually and the dropdown doesnt list anything besides parking and conference, is this a bug? is there a workaround as I need to do this from a user?

 

[sigmaIT]

Update, on 5 of my PBX's this is as described above, just found one PBX that does list all system extensions (ring groups etc) correctly in forwarding rules, and the build is the same as the others!

 

[sigmaIT]

it seems there is a tickbox in options under sytem to show system extensions in phone book this was disabled and preventing the forwarding options being available