pgadmin4 won't use pgpass file

I'm running postgresql 11.1 (via unix socket only) and pgadmin 4.2 on linux.

I have a .pgpass file for the postgres user to a specific database but
pgadmin4 keeps asking for a password. Using psql from the command line
works fine.

my pgpass looks like the following
localhost:5432:newdb:postgres:**********

Setting up a connection to the server in pgadmin4 I tried the following:
General (tab):
Name = newdb admin

Connection (tab):
Host name/address = /var/run/postgresql
Port = 5432
Maintenance database = newdb
Username = postgres

Advanced (tab)
Password file = /home/saultdon/.pgpass

When I hit Save it says,
Unable to connect to server:
fe_sendauth: no password supplied

Where I thought it would use the pgpass file but it doesn't.
So I enter a password in the Connection(tab) just to make the first
connection.

I relaunch pgadmin4 and try to connect to the db but it asks for a password
with the error message:
fe_sendauth: no password supplied
Please enter the password for the user 'postgres' to connect to the server
- "newdb"

I'm not sure what else I need to do to get pgadmin4 to use this .pgpass
file.

Donovan (saultdon)