The SQL Developer Extension Log reports the following warning:

Warning: No extension dependency from org.oddgen.bitemp.sqldev to oracle.ide although org.oddgen.bitemp.sqldev consumes hook javax.ide.extension.ElementName[namespaceURI=http://xmlns.oracle.com/ide/extension, localName=settings-ui-hook] , defined in oracle.ide . The hook will be processed, but is not guaranteed to work every time unless a direct dependency exists.

Adding oracle.ide to the Require-Bundle list in the pom.xml should solve eliminate this warning.