Show all Nodes and Relationships in Data Browser Tab

You can show everything with simple MATCH (n) RETURN n, as offical documentation suggests.

START n=node(*) RETURN n from Neo4j 2.0 is deprecated:

The START clause should only be used when accessing legacy indexes (see Chapter 34, Legacy Indexing). In all other cases, use MATCH instead (see Section 10.1, “Match”).

MATCH (n) OPTIONAL MATCH (n)-[r]-() RETURN n, r;

More simple way is

MATCH (n) RETURN (n)

You may also want to try a cypher query such as:

START n=node(*) RETURN n;

It's very obvious, and it will return all the existing nodes in the database.

EDIT : the following displays the nodes and the relationships :

START n=node(*) MATCH (n)-[r]->(m) RETURN n,r,m;