This section describes how to create a sample widget that lets a logged-in shopper select a different catalog and price groups set on a storefront. The widget makes an endpoint call to get a set of custom order properties. The values of these properties will be used to display the UI for a context selector that a shopper uses to select a catalog and price list groups. The custom widget’s JavaScript file extends the storefront’s ContextViewModel class by implementing a callback function. When a shopper successfully switches context, this function invokes the External Price Group and Catalog webhook, which makes a call to the external system to obtain the catalog and price groups to use.