private void _projectService_ProjectOpened(object sender, EventArgs e)
{
CogProject project = _projectService.Project;
SelectedVariety = null;
VarietiesView = null;
Set("Varieties", ref _varieties, new MirroredBindableList<Variety, VarietiesVarietyViewModel>(project.Varieties, variety => _varietyFactory(variety), vm => vm.DomainVariety));
}