Cannot connect to Oracle database server through SQL Developer but Test works OK I am new to Oracle (from a SQL server and MySQL background) and have just installed Oracle 11g2 Express Edition.

I have downloaded SQL developer which appears to be the Oracle world's equivalent to SSMS.
I have gone to the new connection window, given my connection a name, used SYSTEM as the user and my password that I set up at installation. 
I have left hostname/port/sid as default (localhost/1521/xe respectively)

If I click test I get "status: success" However, if I click the connect button, nothing happens.

What am I missing here?
When you connect from the connection properties dialog, two things will happen in the UI:




the connection icon gets a 'connected' overlay
you get a SQL Worksheet***


If your connection is not successful, you'll get an error message, with the text shown at the bottom of the connection properties window.



***For #2 above, this is conditional on the following preference being enabled, which the default is TRUE.

'Open a Worksheet on connect'