This fixes a crash with GUI elements which are only deleted during GUI
Idle and hold a Reference to a Controllable,
The session is already destroyed at that point:
ARDOUR::CoreSelection::remove_control_by_id(PBD::ID const&)
ARDOUR::AutomationControl::~AutomationControl()
ARDOUR::SlavableAutomationControl::~SlavableAutomationControl()
ARDOUR::MonitorControl::~MonitorControl()
boost::detail::sp_counted_base::destroy()
boost::detail::sp_counted_impl_p<AudioGrapher::Interleaver<float>::Input>::dispose()
boost::detail::sp_counted_base::release()
boost::detail::shared_count::~shared_count()
boost::shared_ptr<PBD::Controllable>::~shared_ptr()
boost::shared_ptr<PBD::Connection>::~shared_ptr()
ArdourWidgets::BindingProxy::~BindingProxy()
ArdourWidgets::ArdourButton::~ArdourButton()
VCAMasterStrip::~VCAMasterStrip()
int idle_delete<VCAMasterStrip>(VCAMasterStrip*)
6f80a5ba0f