Hi Steve,

When igGrid updating has editMode:"row" (default setting) and a cell in a row is in edit mode, then on Tab key the next cell on the right should get focus. If it is last cell in row, then Cancel/Done buttons should get focus. The Tab+Shift should reverse order of focus.
When igGrid updating has editMode:"cell", then on Tab key the next cell on right should get focus and edit mode and on Enter key the next row with same column should get focus. When focus cell is at last column in row, then on Tab key the first column in next row should get focus. The Tab+Shift reverses order.

I tested following sample (you may copy/paste that into body of any html which has js and css resources of igGrid):

<table id="grid2"></table>
<script type="text/javascript">
$(function () {
 $("#grid2").igGrid({
  autoGenerateColumns: true,
  width: 300,
  height: 300,
  features: [{
   editMode: 'cell',
   name: 'Updating'
  }],
  dataSource: [{col1:1, col2:2}, {col1:11, col2:22}, {col1:111, col2:222}]
 });
});
</script>

If you refer to something different, then please give more details or simple codes to reproduce.