Datagrid row height does not change
It's the default padding. You can force to remove the padding this way:
.ui-jqgrid .ui-jqgrid-bdiv tr.ui-row-ltr > td {
padding: 0 !important;
}
.ui-jqgrid .ui-jqgrid-bdiv tr.ui-row-ltr > td {
padding: 0 !important;
}