private void DeleteSelection()
{
if (clbTasks.SelectedIndex != -1)
{
var c = new Change(Environment.UserName, ChangeType.Delete, _curCat.Tasks[clbTasks.SelectedIndex].Clone(),
null);
_curCat.Tasks.RemoveAt(clbTasks.SelectedIndex);
UpdateTasks();
_todoList.AddChange(c);
}
}