jQuery Grid Plugin - jqGrid

I have a function I wrote to add empty rows for my inline editing on my grids.  Since I have multiple grids that I use the function with I made it "generic" and it works great.  Here is the code:

function addEmptyRow(gridName){

// alert('Add a Row');
if(gridName) {
var rowcount = 0;
var ajaxURL;
var objName = gridName[0].id;
// Get the row count from the server
// This could be dangerous if lines have been deleted and added, messing up row counts
ajaxURL = '${.data_model.requestURI}?action=AjaxGetSubRecLastRow&recType='+objName+'&subid='+ $('#emplist').val();

        $.ajax({
          url: ajaxURL,
          async: false,
          cache: false,
          success: function(text){
                  rowcount = text;
                  rowcount++;
                }
 
        });
       
var rc = $(gridName).addRowData(rowcount,{' ':" "},"last"); // duplicate row numbers prevent editing/updating (FYI)

}

}

This will produce a row in the grid with each of the cells being empty AND the editoptions containing the select options will also display.

When I changed the colmodel in my grid to use the formatter:'select' option, the addEmptyRow function stopped returning the select values and the entire cell was missing from the row. I tracked it down to this code around line #283 in jquery.fmatter.js

} else if (!isEmpty(cellval)) {

Since I was passing empty values to the addRowData, the formatter wasn't returning the contents or the cell.  I removed the conditional on !isEmpty and ended up with this:

{ else  {
            if(!cellval)
                cellval = "";

Setting the cellval to ="" seemed to do the trick and so far I haven't seen any downside.  Is there a better way to handle adding an empty row that wouldn't require this "trick" to get the select lists to show?  I *think* this is a bug but it just could be one of those corner cases where the logic doesn't accomodate these values.