I built a form with a new application object and checked it in. Now, I am unable to modify the application object. Why?

After you build a form with a new application object and check it in, an application object is created. The fields that you added to the form are added to the application object. If you need to modify any application object fields, you need to modify the application object directly.

Click Build Application Objects on the Composer Assistant and click All Application Objects. Check out the application object and modify it. After you make the necessary, changes, save and check in the application object.