My guess is that you've already solved this, but changing the theme under Dashboards, under the Management Portlet as admin does change the default theme for dashboards for all users.
Is changing the theme/layout in admin GUI the only way to modify default theme and layout? Is there anywhere in the XML files that we can do this?
Look in the jboss-portal.sar/conf/data/default-object.xml file, and you will see this:
<deployment> <if-exists>keep</if-exists> <context> <context-name>dashboard</context-name> <properties> <!-- | Set the layout for the default portal, see also portal-layouts.xml. --> <property> <name>layout.id</name> <value>generic</value> </property> <!-- | Set the theme for the default portal, see also portal-themes.xml. --> <property> <name>theme.id</name> <value>renaissance</value> </property>
Be warned that changing these settings are only valid the first time you bring up the portal in a new database.