To test that it works, set the ArticleEdit Form as the Startup Form by clicking on the down-arrow next to the ArticleEdit form in the panel on the left. The lightning bolt icon will appear next to ArticleEdit if you’ve done it successfully.
Now run the app. You should see the ArticleEdit Form running, and the dropdown should be populated with your article categories:
Remember to set Homepage back as the Startup Form when you’ve finished.