private bool ContextIsValid()
        {
            // Check if the owning collection is valid - accessing other properites would throw an AccessViolationException!
            if (_context.Collection?.Count != 0)
            {
                return(true);
            }

            // This context is no longer valid, schedule a solution update and return false...
            Dispatcher.BeginInvoke(() => _solution.Update());
            return(false);
        }