How to avoid unselection when selecting a single row in Prim

<p:autoComplete id="estabelecimentos" value="#{questionarioMB.estabelecimentosSelecionados}"
                required="true" widgetVar="autoCompleteEstabelecimento"
                var="estabelecimento" itemLabel="#{estabelecimento.nomefantasia}" itemValue="#{estabelecimento}"
                completeMethod="#{questionarioMB.completeEstabelecimento}" converter="estabelecimentoConverter" multiple="true"
                dropdown="true" emptyMessage="Nenhuma ocorrência" minQueryLength="2"
                resultsMessage="{0} estabelecimentos, use as setas para navegar" scrollHeight="200">
    <p:ajax event="itemSelect" listener="#{questionarioMB.addToEstabelecimentosSelecionados}" />
    <p:ajax event="itemUnselect" listener="#{questionarioMB.removeFromEstabelecimentosSelecionados}" />
</p:autoComplete>
<p:commandButton rendered="#{session.getAttribute('cliente_id') eq 1}" id="btn-carregar-estabelecimentos" icon="ui-icon-triangle-1-s" partialSubmit="true" styleClass="btn-carregar-tabela-dropdown">
    <p:ajax event="click" listener="#{questionarioMB.onCarregarEstabelecimentosClick}" oncomplete="PF('fieldsetEstabelecimentos').toggle()" update="fieldset-estabelecimentos" />
</p:commandButton>
<p:fieldset rendered="#{session.getAttribute('cliente_id') eq 1}" id="fieldset-estabelecimentos" widgetVar="fieldsetEstabelecimentos" collapsed="true" toggleable="true" toggleSpeed="0">
    <p:dataTable caseSensitiveSort="insensitive"
                 currentPageReportTemplate="Pág. {currentPage} de {totalPages}"
                 emptyMessage="Nenhum registro encontrado."
                 id="tabela-estabelecimentos"
                 filterEvent="enter"
                 filteredValue="#{questionarioMB.estabelecimentosFiltrados}"
                 paginator="true"
                 paginatorTemplate="{FirstPageLink} {PreviousPageLink} {CurrentPageReport} {NextPageLink} {LastPageLink}"
                 rowKey="#{rowEstabelecimento.id}"
                 rows="10"
                 rowsPerPageLabel="Ver"
                 rowsPerPageTemplate="10,20,50,100"
                 selection="#{questionarioMB.estabelecimentosSelecionados}"
                 selectionMode="multiple"
                 styleClass="dropdown-tabela"
                 value="#{questionarioMB.estabelecimentos}"
                 var="rowEstabelecimento"
                 widgetVar="table">
        <p:ajax event="rowSelect" listener="#{questionarioMB.onRowSelectEstabelecimentos}" update=":messages:growl inserir_form:estabelecimentos tabela-estabelecimentos" />
        <p:ajax event="rowUnselect" listener="#{questionarioMB.onRowUnselectEstabelecimentos}" update=":messages:growl inserir_form:estabelecimentos tabela-estabelecimentos" />

        <p:column id="coluna-imagem" width="50">
            <i width="50" class="fa fa-check-circle" jsf:rendered="#{questionarioMB.selecionado(rowEstabelecimento)}"></i>
            <i width="50" class="fa fa-times-circle" jsf:rendered="#{questionarioMB.deselecionado(rowEstabelecimento)}"></i>
        </p:column>

        <p:column filterBy="#{rowEstabelecimento.nomefantasia}" filterMatchMode="contains">
            <h:outputText value="#{rowEstabelecimento.nomefantasia}" />
        </p:column>
    </p:dataTable>
</p:fieldset>