title: jqGrid - Custom button in nav bar added multiples times
body: <p>I've added a custom button on my nav bar:</p>
  
  <pre><code>function myFunc(){
  $("#grid").jqGrid({ 
      datatype: 'json',
      url: 'arquivo.jsp',
      jsonReader: {repeatitems: false, root: 'root'},
      pager: '#paginado',
      rowNum: 10,
      autoencode: true,
      rowList: [10,20,30],        
      emptyrecords: "Não há registros.",
      recordtext: "Registros {0} - {1} de {2}",
      loadtext: "Carregando...",
      pgtext: "Página {0} de {1}",
      height: 250,
      width: 700,
      colNames:['Código','Nome', 'Ativo', 'Data Inclusão','Login','Senha','Confirma Senha','Email','Grupos'],
      colModel:[                                    
          {name:'codigo', width:80, sorttype:"int", editable: true, editrules: { edithidden: true }},
          {name:'nome', width:120, editable: true, editrules:{required:true}},
          {name:'ativo', width:80, gridview: true, editable: true, edittype:'select', editoptions:{value:{1:'Sim',2:'Não'}}, editrules:{required:true}},     
          {name:'dataInclusao', width:120, sorttype:"date", datefmt: 'd/M/Y', editable: true, editrules:{required:true, date:true}, editoptions: { dataInit: function(el) { setTimeout(function() { $(el).datepicker({ dateFormat: 'dd/mm/yy' }).val(); }, 200); }}},
          {name:'login', width:80, sortable:true, editable: true, editrules:{required:true}},  
          {name:'senha', width:80, sortable:true, editable: true, hidden:true, edittype:'password', editrules:{edithidden:true, required:true, custom:true, custom_func:validaSenha}},
          {name:'confirmaSenha', width:80, sortable:true, editable: true, hidden:true, edittype:'password', editrules:{edithidden:true, required:true}},
          {name:'email', width:150, sortable:true, editable: true, editrules:{required:true, email:true}} 
      ],
      multiselect: true,
      viewrecords: true,    
      editurl:"data?edit=true",
      caption: "Usuários"}
  );              
  $("#grid").jqGrid('navGrid','#paginado',{},
      {edit:true,url:"teste?acao=edit",closeAfterEdit:true,reloadAfterSubmit:true, 
          beforeShowForm: function(form) {                
              $('#tr_codigo', form).hide(); 
          }, 
          onClickSubmit: function(params, postdata) {
              validaSenha();
          }
      },
      {add:true,url:"teste?acao=teste",closeAfterAdd:true,reloadAfterSubmit:true, 
          beforeShowForm: function(form) { 
              $('#tr_codigo', form).hide(); 
          }, 
          onClickSubmit: function(params, postdata) {
              validaSenha();
          }
      },
      {del:true,reloadAfterSubmit:true, 
          onclickSubmit: function(url, postdata){
              url.url = 'teste?acao=del';
              return {codigo: $('#grid').getCell(postdata, 'codigo')};
          }
      },
      {search:true},
      {refresh:true}
  ).navButtonAdd('#paginado',{
      caption:"", 
      buttonicon:"ui-icon-suitcase", 
      onClickButton: function(){ 
          var dados = $("#grid").jqGrid('getGridParam','selrow');         
      }, 
      position:"last"
  }); 
  </code></pre>
  
  <p>};</p>
  
  <p>but everytime I click on the page that shows my grid, a new button is added as you can see in this image:</p>
  
  <p><img src="https://i.stack.imgur.com/bRlWR.jpg" alt="enter image description here"></p>
  
  <p>I don't know if my .jsp can be bringing on this problem but I definitely can't find where the problem is. Hope you guys can help me</p>
  
  <p>Thanks in advance,</p>
  
  <p>Lucas.</p>