Resolution:
In Basic Mode (when the Advanced Logging button is unchecked)
Designer takes control on providing the 2 default Sinks
(file Sink and stdioSink) with 3 default roles (info,warning.error)
and it takes control for all the other sinks under LogSinks.

User is given an option to delete the roles by unchecking
the check boxes available in Logging tab.
For deleting Info role for all Sinks , user has to uncheck Log InfoMessages.
For deleting Error role for all Sinks, user has to uncheck Log Error Messages.
For deleting Warning Role for all Sinks,user has to uncheck Log Warning Messages.
For deleting the default stdioSink user has to uncheck Log to Standard I/O
For deleting the default FileSink user has to delete the default Log File and Apply.

If the user wants to configure his own Sinks with his own roles then he should not
uncheck this Advanced Logging. In Advanced mode ,user can
decide which roles and which sinks he wants to choose.

What is Advanced Logging in Designer under Logging tab of Generic Adapter configuration?