Getting ready

This recipe is a bit more complex than the previous recipes. So, I'll not explain all the code but only the fundamental parts. You can find the complete code in the book's code repository (Chapter1/RECIPE06).

Let's say we want to create a tabbed interface for our software that is used to manage product orders, sales, and invoices. All the forms must be usable at the same time, without us having to close the previous one. Before we begin, the following screenshot is what we want to create: