SQL Developer 4.2 - user defined extension does not work

I use a user defined extension to show table comments. It works in older versions of SQL Developer, but the tab does not appear in 4.2.

<items> <item type="editor" node="TableNode" vertical="true">

<title><![CDATA[Comments]]></title>

<query>

<sql><![CDATA[select comments from ALL_TAB_COMMENTS where owner = :OBJECT_OWNER and table_name = :OBJECT_NAME]]>

</sql>

</query>

</item>

</items>