title: jqGrid SetCell and SaveCell blanking out the cell after closing a modal dialog
body: <p>I have a cell-editable jqgrid with a column that has an edittype of 'button'.  When the cell is clicked, the button appears.  when the button is clicked, a modal dialog appears allowing the user to select a value from a grid.  This is all working fine.</p>
  
  <p>When the user clicks the 'OK' button on the modal dialog after picking a value from the grid, I'd like to set the cell value with the value selected by the user and save the cell.  </p>
  
  <p>Instead of setting and saving the cell value, the cell is blanked out.  Not sure why.  </p>
  
  <p>Here is the relevant jqGrid / modal dialog code:</p>
  
  <pre><code>// global variables
  base.selectedCode = null;
  base.liaGridSelectedId = null;
  base.liaGridSelectedICol = null;
  base.liaGridSelectedIRow = null;
  
      $("#liaGrid").jqGrid({
          datatype: "local",
          data: base.liaGridData,
          cellEdit: true,
          cellsubmit: 'clientArray',
          height: 140,
          colNames: ['ID', 'Class Code', 'State', 'Location Type'],
          colModel: [
                      { name: 'id', index: 'id', width: 90, sorttype: "int", editable: false, hidden: true },
                      { name: 'ClassCode', index: 'ClassCode', width: 90, sortable: false, editable: true, edittype: "button",
                          editoptions: {
                              dataEvents: [{
                                  type: 'click',
                                  fn: function (e) {
                                      e.preventDefault();
                                      var rowid = $('#liaGrid').jqGrid('getGridParam', 'selrow');
                                      base.liaGridSelectedId = parseInt(rowid);
                                      $('#class-dialog').dialog('option', { width: 100, height: 200, position: 'center', title: 'Pick a Class' });
                                      $('#class-dialog').dialog('open');
  
                                      return true;
                                  }
                              }]
                          }
                      },
                      { name: 'LocationType', index: 'LocationType', width: 90, sortable: false, editable: true, edittype: "select", editoptions: { value: "0:;1:Rural;2:Suburban;3:Urban"} }
                  ],
          caption: "Liability Model",
          beforeEditCell: function (rowid, cellname, value, iRow, iCol) {
              base.liaGridSelectedICol = iCol;
              base.liaGridSelectedIRow = iRow;
          }
      });
  
  
      var infoDialog = $('#class-dialog').dialog({
          autoOpen: false,
          modal: true,
          show: 'fade',
          hide: 'fade',
          resizable: true,
          buttons: {
              "Ok": function () {
                  if (base.selectedCode != null) {
  
                      $("#liaGrid").jqGrid('setCell', base.liaGridSelectedId, 'ClassCode', base.selectedCode);
  
                      $("#liaGrid").jqGrid('saveCell', base.liaGridSelectedIRow, base.liaGridSelectedICol);
  
                      $(this).dialog("close");
                  }
              },
              "Cancel": function () {
                  $(this).dialog("close");
              }
          }
  
      });
  </code></pre>
  
  <p>As seen above, I'm attempting to use jqGrid('setCell') and jqGrid('saveCell') to update and save the contents of the cell.  Not sure why this fails to succeed.</p>