You may use controls to obtain behavior that is not available in PowerCOBOL otherwise.
For example, you may have noticed that if you attempt to create a project that has an execution module containing 2 or more separate forms, you cannot access one form's methods and properties from another form - even though they are controlled by the same application module.
You can get around this restriction, however, if you create the other forms in a separate control and then insert them into your project module's main form.