Steps to reproduce the problem:
Execute the following SQL sentence against any database:
create table Employee(
id integer not null primary key,
name varchar(50) not null,
foreign key (bossId) references Employee(id)
Open SQuirreL, connect to the database, and open the graph
diagram of "Employee" table.
The corresponding SQuirreL's graph diagram to that
table does NO show the edge between an employee
("bossId" column) and itself ("id" column).