For the following reasons Silk Test Classic might recognize a control as a custom control:
The control is not named with the standard name upon the definition of the control in the application under test. For example, when a TextField is named EnterTextRegion. If this is the only reason why Silk Test Classic recognizes the control as a custom control, then you can class map the control to the standard name.
The class mapping might not work. The class mapping will work if the control is not really a custom control, but rather a standard control with a non-standard name. Try this as your first attempt at dealing with a custom control.
When you are using the Classic Agent, the support for custom controls depends on whether the control is a graphical control, such as a tool bar, or a non-graphical control, such as a text box.