Hello DQ ninh,

I know it may be a late response but here is what worked for me:

Under the  ig_res directory you need to edit the ig_dataGrid.css file (it is located in the Default subdirectory unless you are using a custom style set)

Within ig_dataGrid.css, seek for these :

.igg_HeaderCaption          --> it controls appearance of the header title area

tbody.igg_Item>tr>td        --> it controls appearance of the data rows

tbody>tr.igg_Alt>td          --> it controls appearance of the alternating data rows

you will need to add style properties in order to show separator lines, as in this sample code:

.igg_HeaderCaption
{
font-size: 10px;
font-weight:normal;
padding-left:4px;
overflow: hidden;
text-align:left;
color:White;
white-space:nowrap;
border-left:1px;                   /*width of line separator*/
border-left-style:solid;      /*style of line separator*/
border-color:black;            /*color of line separator*/
}

hope it will help!

regards,

Claudio