rownnumber is not displaying when toolbar serach and grouping is used

My problem is rownumber is not displaying when i use toolbar search and grouping togather , if i use them indivially i can see the rownnumber in the grid. My grid is like this

<sjg:grid id="reportGrid" gridModel="gridModel" autowidth="true" filter="true"  
    filterOptions="{stringResult:true,searchOnEnter:false,defaultSearch:'cn'}"    
    groupColumnShow="false" 
    groupField="['col','col1']" onSuccessTopics="dataLoadCompleted"
    groupText="['col: {0}       Total : {1} ','col2: {0}        Total : {1}']"
    href="rpt" formIds="reportform" loadonce="true">
    ....................................
    ....................................
    .................................
</sjg:grid>
</s:else>

<script type="text/javascript">
    jQuery(document).ready(function () {    
         $.subscribe('gridLoadComplete', function(event, data) {
             $("#reportGrid").jqGrid('setGridParam', { ignoreCase: true});
        }); 
     });
</script>

Any idea what might be wrong here?

Solution

It's limitation of grouping. See the documentation

When the grouping is enabled, the following options will be set explicit into the code:

...

rownumbers = false;

...