Oracle 11G: How to disable the default scheduler maintenance Window for good?

Some workshops go by canceling the scheduler default scheduler maintenance window and prefer to manage  statistics manually, by this having more control; besides, they don't want to overload the machine at any time.

So the run:

SQL>ALTER SYSTEM SET RESOURCE_MANAGER_PLAN = '' SCOPE=BOTH;

Surprisingly, the alert log shows that the maintenance window keeps being activated, see sample of excerpt:

Setting Resource Manager plan SCHEDULER[0x2C44]:DEFAULT_MAINTENANCE_PLAN via scheduler window

Setting Resource Manager plan DEFAULT_MAINTENANCE_PLAN via parameter

Solution:

SQL> ALTER SYSTEM SET RESOURCE_MANAGER_PLAN = 'FORCE:' scope=both;

After this, the maintenance plan default window is gone, for good.