with the facelet page :-
<ui:composition xmlns="http://www.w3.org/1999/xhtml"
                xmlns:s="http://jboss.com/products/seam/taglib"
                xmlns:ui="http://java.sun.com/jsf/facelets"
                xmlns:f="http://java.sun.com/jsf/core"
                xmlns:h="http://java.sun.com/jsf/html"
xmlns:ice="http://www.icesoft.com/icefaces/component"
                template="layout/template.xhtml">
                       
<ui:define name="body">
    
    <h:messages globalOnly="true" styleClass="message" id="globalMessages"/>
    
    <ice:form id="testEditTemplate" styleClass="edit">
        
        <ice:panelGroup styleClass="edit">
            
            
          <s:decorate template="layout/display.xhtml">
                <ui:define name="label">firstName</ui:define>
                <h:inputText id="firstName" value="first testValue using s:decorate"/>
            </s:decorate>
            
            <ui:decorate template="layout/display.xhtml">
                <ui:define name="label">firstName</ui:define>
                <h:inputText id="firstName" value="second testValue using ui:decorate"/>
            </ui:decorate>
            
        </ice:panelGroup>
    </ice:form>
   </ui:define>
</ui:composition>

and the following template:-
<ui:composition xmlns="http://www.w3.org/1999/xhtml"
                 xmlns:ui="http://java.sun.com/jsf/facelets"
                 xmlns:h="http://java.sun.com/jsf/html"
                 xmlns:f="http://java.sun.com/jsf/core">
                 
    <div class="prop">
        <span class="name">
            <ui:insert name="label"/>
        </span>
        <span class="value">
            <ui:insert/>
        </span>
    </div>
    
</ui:composition>

either instance (the s:decorate and the ui:decorate) do not understand the flowthrough of the class="value" of the template and get the following error:-

18:07:43,803 ERROR [D2DFaceletViewHandler] Problem in renderResponse: Nested form found on the page. The form action element can not be nested
javax.faces.FacesException: Nested form found on the page. The form action element can not be nested
at com.icesoft.faces.renderkit.dom_html_basic.FormRenderer.validateNestingForm(FormRenderer.java:362)
at com.icesoft.faces.renderkit.dom_html_basic.FormRenderer.validateNestingForm(FormRenderer.java:365)
at com.icesoft.faces.renderkit.dom_html_basic.FormRenderer.validateNestingForm(FormRenderer.java:365)
at com.icesoft.faces.renderkit.dom_html_basic.FormRenderer.validateNestingForm(FormRenderer.java:365)
at com.icesoft.faces.renderkit.dom_html_basic.FormRenderer.validateNestingForm(FormRenderer.java:365)
at com.icesoft.faces.renderkit.dom_html_basic.FormRenderer.encodeBegin(FormRenderer.java:83)
at javax.faces.component.UIComponentBase.encodeBegin(UIComponentBase.java:512)