To create a class, the class you are subclassing from must be visible to your application. To be visible means that the class is in your application's prerequisite chain.

Return to an Application Manager. (Select Manage Applications from the Tools menu.) With DevelopChooser highlighted in the list of applications, select Browse Application from the Applications menu. If your system is set to the standard browsers, an Application Browser opens on your application.

Note that there are only a few classes listed in this browser. This is because the scope of the browser is limited to only those classes contained in your application. The Application Browser displays the inheritance chain from class Object to class DevelopChooser. Because you will be subclassing from Object, you can see that Object is visible to your application.