In JavaFX App_browser.jnlp file if we mention the following jnlp options
<property name="jnlp.packEnabled" value="true"/>
<property name="jnlp.versionEnabled" value="true"/>

the draggable Applet feature does not work with 6u12_b04 whereas it works with 6u10 and 6u11 builds

For more information please look at the JavaFX bug
http://javafx-jira.kenai.com/browse/RT-3332