I searched hi and low for information regarding Waves plug-ins .. and wound up calling tech-support.
So, here goes:
Problem: Waves V6 Plug-in GUI controls are not visible in Sonar 8
Description
If you use Waves Version 6 plugins, the GUI controls for the
plug-ins will not be visible if the X-Ray option is enabled.
While the plug-ins are functional, the Fx dialog will be blank.
Solution:
To disable the X-ray option, go to the Options Menu, choose Global...
Then, in the "General" tab (at the bottom of the dialog), uncheck
the "Enable X-Ray" option.
Close and re-open and Waves Fx dialogs you may have open. The GUI should
now appear.