I'm trying to create a Drilldown table, which leads to another Table once clicking on the Year row.

I've changed the drilldown Sales By Time example to use a table with a search option. However, I can't get the Year Row to be clickable to the next Table.
Here is the Drilldown Section code in MyReport.view.php:
DrillDown::create(array(
        "name"=>"DelvRef",
        "title"=>"Summary of Councils",
        "levels"=>array(
            array(
                "title"=>"All Years",
                "content"=>function($params,$scope)
                {
                    Table::create(array(
							"dataStore"=>$this->dataStore("result"),
							//"removeDuplicate"=>array("customerName","orderNumber"),
							"cssClass"=>array(
								"table"=>"table table-bordered"
							),
							"columns"=>array(
								"DelvRef"=>array(
									"label"=>"DelvRef",
								),
								"SourceType"=>array(
									"label"=>"Source Type",
									"type"=>"string",
								),
								"Invoice_Value"=>array(
									"label"=>"Invoice Value",
									"prefix"=>"£",
								),
								"ClaimTotal"=>array(
									"label"=>"Claim Total",
									"prefix"=>"£",
								),
								"PaymentYear"=>array(
									"label"=>"Year",
									"type"=>"string",
								)
							),
							"clientEvents"=>array(
                            "itemSelect"=>"function(params){
                                DelvRef.next({year:params.selectedRow[04]});
                            }",
                        )
						));
                }
            ),
			
			
            array(
                "title"=>function($params,$scope)
                {
                    return "Year ".$params["year"];
                },
                "content"=>function($params,$scope)
                {
                            Table::create(array(
								"dataStore"=>$this->dataStore("councilsResults"),
								//"removeDuplicate"=>array("customerName","orderNumber"),
								"cssClass"=>array(
									"table"=>"table table-bordered"
								),
								"columns"=>array(
									"FY"=>array(
										"label"=>"FinancialYear",
									),
									"KnownAs"=>array(
										"label"=>"Name",
										"type"=>"string",
									),
									"DelvRef"=>array(
										"label"=>"DelvRef"
									),
									"SourceType"=>array(
										"label"=>"SourceType",
										"prefix"=>"",
									),
									"RK"=>array(
										"label"=>"Rank",
													),
									"TotalInvoiceAmount"=>array(
										"label"=>"Invoice Value",
										"prefix"=>"£",
													),
									"Claim_Total"=>array(
										"label"=>"Claim Value",
										"prefix"=>"£",
									)
								)
							)); //end of Table:Create
                }        
            )
        ),
        "themeBase"=>"bs4",
    ));

