When StyleVision is opened for the first time, the Messages sidebar (screenshot below) is displayed below the Main Window of the GUI. To toggle the Messages sidebar on and off, click View | Messages.
The Messages sidebar displays warnings in Design View and Authentic View. In Design View, the warnings relate to various aspects related to the SPS document, from a missing Working XML File to errors in the design structure. In Authentic View, the warnings are about the validity of the XML data entered, whether valid according to the underlying schema or according to additional validation criteria.