To remedy this, our Service Portal developer (Kim) built a custom "Try in Portal" UI Action, which does just what you might expect - it allows you to preview your catalog item in the Service Portal.

What's more, it allows you to actually choose which Portal you'd like to view the catalog item in! This way, you can verify that any themes, JS Includes or other client-side code you have running on that particular Service Portal.

There are two components to this functionality: a UI Action, and a UI Page (inspired by the "Try it" button on Service Portal pages).

When clicking Try in Portal on a Catalog Item, you'll be presented with a dialog which asks you to select which portal you'd like to view the catalog item in (see the screenshot on the left).