After running a compare, the results are displayed. But if synonym is selected to display more information, the following exception is thrown:
Exception: System.ArgumentException
Message : Try create tree item for group type
This occurs for any synonym but does not seem to be a problem for displaying details of any other object comparison.
WORKAROUND:
None. Toad seems to be responsive and workable even after the error and still seems to display the synonym information.
STATUS:
Waiting for fix in a future version of Toad for SQL Server.