According to the documentaton the #connector_select_filter will autopopulate distinct values when no specific options are passed to the method connector.ExplicitOptions.Add();
From Documentation -( automatic - if no custom instruction provided , grid will use DISTINCT select against related field, and fetch all possible options)
Below is my code. This produces no drop down values. I would expect it to have all existing values based on the documentation. I have also tried this without including the line - connector.ExplicitOptions.Add((TableField)“RateEffDate”);
public override IdhtmlxConnector CreateConnector(HttpContext context)
{
string parentEngID = “”;
if (context.Request.QueryString[“peid”] != null)
{
parentEngID = context.Request.QueryString[“peid”].ToString();
}
dhtmlxGridConnector connector = new dhtmlxGridConnector(
"SELECT RateEffDate, RateEndDate, EmployeeNumber, EmployeeName, SkillLevel, " +
"AllocatedHours, Rate, FBillingTask, TBillingTask, OverSight, InDate, OutDate, " +
"ObjectAccountF, ObjectAccountT, NotToExceedDollars, NotToExceedUnits, InvoiceType, " +
"POLineNumber, SubmittedBy " +
“FROM TBillRate WHERE ParentEngagementID = '” + parentEngID + “’”,
“StaffingID”,
dhtmlxDatabaseAdapterType.SqlServer2005,
ConfigurationManager.ConnectionStrings[“CEIConnectionString”].ConnectionString, “ParentEngagementID”
);
connector.ItemPrerender += new EventHandler<ItemPrerenderEventArgs>(connector_ItemPrerender);
connector.Request.TransactionMode = TransactionMode.PerRecord;
connector.ExplicitOptions.Add((TableField)“RateEffDate”);
return connector;
}
Also, I know I am asking alot of questions. I hope you don’t mind 
.
Thanks,
Jim
You need to comment the next line
connector.ExplicitOptions.Add((TableField)“RateEffDate”);
If you want to use automatic distinct list - you must not define any options rules for related column. Above instruction just sets the empty list of values for the related select element.