When we create a Seam Web Project with JBoss Seam Portlet Facet, JBDS generates a duplicate entry for view-handler in faces-config.xml as follow:

<?xml version="1.0" encoding="UTF-8"?>

<faces-config
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-facesconfig_1_2.xsd"
version="1.2">
<application>
<view-handler>com.sun.facelets.FaceletViewHandler</view-handler>
<view-handler>org.jboss.portletbridge.application.PortletViewHandler</view-handler>
<state-manager>org.jboss.portletbridge.application.PortletStateManager</state-manager>
<locale-config>
<default-locale>en</default-locale>
<supported-locale>bg</supported-locale>
<supported-locale>de</supported-locale>
<supported-locale>en</supported-locale>
<supported-locale>fr</supported-locale>
<supported-locale>tr</supported-locale>
</locale-config>
</application>

</faces-config>

We should remove the entry:

<view-handler>com.sun.facelets.FaceletViewHandler</view-handler>