The ResourcesPopupCheckedListBoxControl class represents a supplementary control that allows a user to filter resources in the attached scheduler. To attach a scheduler to the control, use the SchedulerControl property. When you drop the control from the toolbox to a form that already contains a scheduler, the property is specified automatically.
In the figure below, you can see how the control filters resources in the attached scheduler.

System.Object
System.MarshalByRefObject
System.ComponentModel.Component
System.Windows.Forms.Control
ControlBase
BaseControl
BaseEdit
TextEdit
ButtonEdit
PopupBaseEdit
PopupContainerEdit
ResourcesPopupCheckedListBoxControl
AppointmentResourcesEdit