/// <summary>
            /// Creates and show content.
            /// </summary>
            private void _CreateAndShowContent()
            {
                Dispatcher = Dispatcher.CurrentDispatcher;
                var source = new VisualTargetPresentationSource(_hostVisual);

                _sync.Set();
                source.RootVisual = _createContent();
                DesiredSize       = source.DesiredSize;
                _rootVisual       = source.RootVisual as Control;
                Debug.Assert(null != _rootVisual);
                _invalidateMeasure();

                Dispatcher.Run();
                source.Dispose();
            }
            /// <summary>
            /// Creates and show content.
            /// </summary>
            private void _CreateAndShowContent()
            {
                Dispatcher = Dispatcher.CurrentDispatcher;
                var source = new VisualTargetPresentationSource(_hostVisual);
                _sync.Set();
                source.RootVisual = _createContent();
                DesiredSize = source.DesiredSize;
                _rootVisual = source.RootVisual as Control;
                Debug.Assert(null != _rootVisual);
                _invalidateMeasure();

                Dispatcher.Run();
                source.Dispose();
            }