Silk Test Workbench filters out certain controls that are typically not relevant for functional testing. For example, controls that are used for layout purposes are not included. However, if a custom control derives from an excluded class, specify the name of the related WPF class to expose the filtered controls during recording and playback.Specify the names of any WPF classes that you want to expose during recording and playback. For example, if a custom class called MyGrid derives from the WPF Grid class, the objects of the MyGrid custom class are not available for recording and playback. Grid objects are not available for recording and playback because the Grid class is not relevant for functional testing since it exists only for layout purposes. As a result, Grid objects are not exposed by default. In order to use custom classes that are based on classes that are not relevant to functional testing, add the custom class, in this case MyGrid, to the OPT_WPF_CUSTOM_CLASSES option. Then you can record, playback, find, verify properties, and perform any other supported actions for the specified classes.