When the panelCollapsible component is used within a composition component tag and it´s expanded attribute is controlled via the composite.attrs.expanded attribute, the component will no longer function. For example:

<composite:interface>
........
<composite:attribute name="expanded" required="false" default="true"/>
</composite:interface>

<composite:implementation>
<ice:panelCollapsible styleClass="portlet" expanded="#{cc.attrs.expanded}" rendered="#{cc.attrs.show}">
<f:facet name="header">
.........
</composite:implementation>

It appears as though the following POST is sent to the server but a response is not returned:

<partial-response>
<changes>
<update id="javax.faces.ViewState">-3641179103414494187:837983854702968234</update>
<eval>document.getElementById('form:j_idt7:j_idt8').getElementsByTagName('a')[0].focus();//903991920</eval>
</changes>
</partial-response>

Test case intended for deployment on Tomcat attached.