protected override void InitDefaultLayout()
        {
            var panels = new List <PanelWorkspaceViewModel> {
                _ToolboxViewModel, _SolutionExplorerViewModel, _PropertiesViewModel, _ErrorListViewModel
            };

            foreach (var panel in panels)
            {
                OpenOrCloseWorkspace(panel);
            }
            PanelWorkspaceViewModel document = CreateDocumentViewModel();

            document.Open();
            OpenOrCloseWorkspace(document, true);
        }
 protected override void OnPreviewItemChaged()
 {
     if (this.previewItem != null)
     {
         if (this.previewItem.IsPreview)
         {
             this.previewItem.IsPreview = false;
             this.previewItem.IsClosed  = true;
         }
     }
     previewItem = CreateDocumentViewModel();
     previewItem.Open();
     previewItem.ShowPinButton = true;
     previewItem.Pinned        = true;
     OpenOrCloseWorkspace(previewItem, true);
     previewItem.IsPreview = true;
 }