Unless placed by law or expressly exempted from placement by law, the officers and units in the Executive Branch of the State government that are not principal departments may be placed by the Governor in any principal department. Unless expressly exempted from placement by law, an interstate, regional, or other intergovernmental unit in which the State participates shall be placed in the appropriate principal department. Notwithstanding the placement of a unit in a principal department: the powers and duties that are assigned by law to the unit are not changed; a State officer or State employee who is not in the State Personnel Management System and is transferred with the unit remains exempt from the provisions of the State Personnel and Pensions Article unless the officer or the employee is placed in the State Personnel Management System in accordance with those provisions; and the head of a unit who is in the State Personnel Management System or holds the position other than at the pleasure of the Governor does not cease to be in the State Personnel Management System or to hold the position other than at the pleasure of the Governor.