date="tree products"
                                 oncomplete="initDND()"/>

                <p:tree id="tree" value="#{columnManagerView.availableColumns}" var="column" style="margin-bottom:20px">
                    <p:treeNode>
                        <h:outputText value="#{column}"/>
                    </p:treeNode>

                    <p:treeNode type="column" icon="pi pi-ellipsis-v">
                        <h:outputText value="#{column.property}"/>
                    </p:treeNode>
             