The PostgreSQL module is showing the wrong set of
rights granted on a table. For example, it is showing
INSERT and SELECT rights when I know (from psql) that
the user only has SELECT rights. But this depends on
the name of the user who granted the rights, because of
an apparent problem parsing the RELACL values.
What seems to be happening is that edit_grant.cgi is
trying to match the code letters r,w,a,d (etc, where
r=select, a=insert...) to the permissions returned by a
query on the relacl field. The webmin module expects
the field to contain just these letters after
separating the two parts, for example "myname=ra" means
user 'myname' has rights 'ra'. But the relacl field
also contains the name of the user who granted this
right, after a slash. So the actual value is
"myname=ra/otheruser". If 'otheruser' has an 'a' in it,
then it looks like you have INSERT rights because 'a'
matches the username.