"The parameters dictionary contains a null entry" while adding a widget

Hi everyone.
I want to add data to the order details in admin section. Because I want to minimize changes of the core code I've decided to add a widget calling in view and create a widget.
So in file _OrderDetails.Shipping.cshtml I've added:

@Html.Widget("order_shipping_info_bottom", Model.Id)

Widget has following methods implemented:

        public void GetDisplayWidgetRoute(string widgetZone, out string actionName, out string controllerName,
            out RouteValueDictionary routeValues)
        {
            controllerName = "ShoppingCartWeight";
            routeValues = new RouteValueDictionary
            {
                {"Namespaces", "Nop.Plugin.Ralfeus.ShoppingCartWeight.Controllers"},
                {"area", null},
                {"widgetZone", widgetZone}
            };

            switch (widgetZone)
            {
                case "order_summary_cart_footer":
                    actionName = "Cart";
                    break;
                case "productdetails_before_collateral":
                    actionName = "ProductDetails";
                    break;
                case "order_shipping_info_bottom":
                    controllerName = "AdminOrderWeight";
                    actionName = "OrderShipping";
                    break;
                default:
                    actionName = null;
                    break;
            }

        }

        [ChildActionOnly]
        public ActionResult OrderShipping(int orderId)
        {
            var primaryWeight = this._measureService.GetMeasureWeightById(this._measureSettings.BaseWeightId);
            var order = _orderService.GetOrderById(orderId);
            decimal orderWeight = 0;
            foreach (var orderItem in order.OrderItems)
            {
                var product = _productService.GetProductById(orderItem.ProductId);
                orderWeight += product.Weight;
            }
            var model = new ShoppingCartWeightModel
            {
                Weight =
                    $"{orderWeight:N0} {primaryWeight.Name}"
            };
            return PartialView("~/Plugins/Ralfeus.ShoppingCartWeight/Views/AdminOrderWeight/_Shipping.cshtml", model);
        }

When I try to open order details page I get following exception:

The parameters dictionary contains a null entry for parameter 'orderId' of non-nullable type 'System.Int32' for method 'System.Web.Mvc.ActionResult OrderShipping(Int32)' in 'Nop.Plugin.Ralfeus.ShoppingCartWeight.Controllers.AdminOrderWeightController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter.
Parameter name: parameters

I've checked that while calling widget order ID is passed. What could go wrong?

are you passing it as 'orderId' and not id? check your route to ensure the parameter name is correct.

I'm not passing a parameter by name at all. I just pass a value:

@Html.Widget("order_shipping_info_bottom", Model.Id)

I saw same widget call in core code and used it actually in same plugin:
Here widget is called in ProductTemplate.Simple.cshtml:

@Html.Widget("productdetails_before_collateral", Model.Id)

and here I implement widget for this call:

        public void GetDisplayWidgetRoute(string widgetZone, out string actionName, out string controllerName,
            out RouteValueDictionary routeValues)
        {
            controllerName = "ShoppingCartWeight";
            routeValues = new RouteValueDictionary
            {
                {"Namespaces", "Nop.Plugin.Ralfeus.ShoppingCartWeight.Controllers"},
                {"area", null},
                {"widgetZone", widgetZone}
            };

            switch (widgetZone)
            {
                case "order_summary_cart_footer":
                    actionName = "Cart";
                    break;
                case "productdetails_before_collateral":
                    actionName = "ProductDetails";
                    break;
                case "order_shipping_info_bottom":
                    controllerName = "AdminOrderWeight";
                    actionName = "OrderShipping";
                    //routeValues["area"] = "Admin";
                    break;
                default:
                    actionName = null;
                    break;
            }

        }

        [ChildActionOnly]
        public ActionResult ProductDetails(int productId)
        {
            var primaryWeight = this._measureService.GetMeasureWeightById(this._measureSettings.BaseWeightId);
            var product = _productService.GetProductById(productId);
            var model = new ShoppingCartWeightModel
            {
                Weight =
                    $"{product.Weight:N0} {primaryWeight.Name}"
            };
            return PartialView("~/Plugins/Ralfeus.ShoppingCartWeight/Views/ShoppingCartWeight/ProductDetails.cshtml", model);
        }

And this code works just fine. I see no difference between my call of widget and this one.