TreeTable - Column Resize Columns can be resized in two ways, with a helper or live.
Basic
NameSizeType
Live
NameSizeType
<h:form>
    <p:treeTable value="#{ttBasicView.root}" var="document" style="margin-bottom:20px" resizableColumns="true">
        <f:facet name="header">
            Basic
        </f:facet>
        <p:column headerText="Name">
            <h:outputText value="#{document.name}" />
        </p:column>
        <p:column headerText="Size">
            <h:outputText value="#{document.size}" />
        </p:column>
        <p:column headerText="Type">
            <h:outputText value="#{document.type}" />
        </p:column>
    </p:treeTable>

    <p:treeTable value="#{ttBasicView.root}" var="document" resizableColumns="true" liveResize="true">
        <f:facet name="header">
            Live
        </f:facet>
        <p:column headerText="Name">
            <h:outputText value="#{document.name}" />
        </p:column>
        <p:column headerText="Size">
            <h:outputText value="#{document.size}" />
        </p:column>
        <p:column headerText="Type">
            <h:outputText value="#{document.type}" />
        </p:column>
    </p:treeTable>
</h:form>
                
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