In a sandboxed app, an NSOpenPanel doesn't display sockets, e.g. /tmp/mysqld.sock
The sockets do appear if you use
[urlArr setArray:[fm contentsOfDirectoryAtPath:selectedFilePath error:&err]];
urlArr contains the socket. But it hasn't been selected by the user, so you can't create a bookmark or request secure access.
I have incoming/outgoing connections allowed, and also tried with secure access to the folder and then creating a bookmark to the socket, doesn't work. Is it simply not possible to select sockets in a sandboxed app?