This post provides information about the Exceptions from the Source Details - Exceptions tab:
The Exceptions from the Drop-down menu are coming from the AUN_EXCEPTION_CATEGORY table in the HPeD database:
If you do not want to see those exception under the Exception category, you can delete the contents of the AUN_EXCEPTION_CATEGORY table and add only the exceptions that you want to see.
You can add exceptions from the Source Details - Summary:
When you add an Exception, you need to use the IMPORTERRORCODE IDOL field.
After that, you will only see the exception that you added: