jQuery Grid Plugin - jqGrid

I'm initializing the grid like so:

    $("#mainGrid").jqGrid({
  url : g_MainGridUrl,
  datatype : 'json',
  height : 460,
  autowidth : true,
  colNames : g_ColNames,
  colModel : g_ColModel,
  pager : '#pager',
  rowNum : 100,
  rowList : [100, 200, 300],
  sortname : g_DefaultSort,
  sortorder : 'desc',
  sortable: true,
  viewrecords : true,
  caption : 'Results',
  hidegrid : false,
  rownumbers : true,   
  jsonReader : {
   root : "ROWS",
   page : "PAGE",
   total : "TOTAL",
   records : "RECORDS",
   cell : "",
   id : g_DefaultSort
  },
  loadComplete: function(){
   var num_records = $('#mainGrid').getGridParam('records');
   $('#gview_mainGrid div.ui-jqgrid-titlebar span').html('Results: '+num_records);
  },
  loadBeforeSend : function(thisXhr) {
   xhr = thisXhr;
  },
  ondblClickRow: function(rowid) {
      jQuery(this).jqGrid('viewGridRow', rowid, { width: "500″});
  }
 });
 
 $("#mainGrid").jqGrid('navGrid', '#pager', {
  del : false,
  add : false,
  edit : false,
  refresh:false,
  search: false,
  view: true
 });
 
 $("#mainGrid").jqGrid('navButtonAdd','#pager',{
  caption: "Columns",
  title: "Reorder Columns",
  onClickButton : function (){
   $("#mainGrid").jqGrid("columnChooser", {
        done: function() {
          resize_the_grid();
       },
    height: 320
     });
  }
 });

and calling the grid like so, after building a filter Object:

    $('#mainGrid').setGridParam({
   url : g_MainGridUrl + Ext.util.JSON.encode(filter)
  });
 $('#mainGrid').trigger("reloadGrid"); 

As the subject states, when I double-click on a row to view its record and then change rows from the modal dialog, not all columns get updated – some do, but not others. I thought it might be because I didn't have <th>s defined for the table, so I tried adding them. I have downloaded the most recent version (4.2.0). Any ideas?

UPDATE: I think I've found the cause, but still don't have a solution. It seems that any column that has a title with a space in the name can't read the grid correctly. I confirmed by adding underscores to replace the spaces in the titles, and found that for each column corrected, its values began updating. I'm filing a bug report.