I am trying to add the CustomerRefNbr field to the Orders screen (SP504010) here:

I’ve tried a LOT of different things. The .ts file compiles without any complaints but the field does not show. I’m not good at this, so hopefully I’m just making a s-t-u-p-i-d mistake.
I think the source code I am trying to extend is "src/screens/SP/order/view-models"
I think I should be adding the field to the PXView on that file.
Here is my .ts code. If anyone see’s anything, let me know!
import {
PXFieldState,
PXView,
readOnly,
} from "client-controls";
import { AllOrdersLine, OpenOrdersLine, OrdersLine } from "src/screens/SP/order/view-models";
export interface SP504010_OrdersLine extends OrdersLine { }
export class SP504010_OrdersLine extends PXView {
@readOnly CustomerRefNbr: PXFieldState;
}
export interface SP504010_AllOrdersLine extends AllOrdersLine { }
export class SP504010_AllOrdersLine extends OrdersLine {
}
export class SP504010_OpenOrdersLine extends OpenOrdersLine {
}