void HandleSelectionDidChange (object sender, EventArgs e) {
using (var a = new NSAutoreleasePool ()) {
BeginInvokeOnMainThread(delegate {
if (TableView.SelectedRowCount > 0) {
TableRowMenuOpen.Enabled = false;
foreach (int row in TableView.SelectedRows) {
var item = DataSource.GetTransmissionItem(row);
if (item != null && item.Done) {
TableRowMenuOpen.Enabled = true;
break;
}
}
TableView.Menu = TableRowContextMenu;
} else {
TableView.Menu = new NSMenu();
}
});
};
}