Can see some folks have found the DisplayOptionInitialize event, still they are in doubt on how to control the displayOption settings based on the selected line.
Here is the solution:
X++:
[FormDataSourceEventHandler(formDataSourceStr(Form1, SalesTable), FormDataSourceEventType::DisplayOptionInitialize)]
public static void SalesTable_OnDisplayOptionInitialize(FormDataSource sender, FormDataSourceEventArgs e)
{
FormDataSourceDisplayOptionInitializeEventArgs args = e as FormDataSourceDisplayOptionInitializeEventArgs;
RecId currentRecId = args.record().RecId;
int rgbValue = 255 - (20 * (currentRecId mod 2));
args.displayOption().backColor(WinAPI::RGB2int(rgbValue, rgbValue, rgbValue));
}