class Bundle;
class Butler;
class Click;
-class ControllableDescriptor;
class CoreSelection;
class ExportHandler;
class ExportStatus;
boost::shared_ptr<PBD::Controllable> controllable_by_id (const PBD::ID&);
boost::shared_ptr<AutomationControl> automation_control_by_id (const PBD::ID&);
- boost::shared_ptr<PBD::Controllable> controllable_by_descriptor (const ARDOUR::ControllableDescriptor&);
void add_controllable (boost::shared_ptr<PBD::Controllable>);
void remove_controllable (PBD::Controllable*);