void ShowAllItems()
        {
            AllItemsViewModel workspace =
                this.Workspaces.FirstOrDefault(vm => vm is AllItemsViewModel)
                as AllItemsViewModel;

            if (workspace == null)
            {
                workspace = new AllItemsViewModel();
                this.Workspaces.Add(workspace);
            }

            this.SetActiveWorkspace(workspace);
        }
        void ShowAllItems()
        {
            AllItemsViewModel workspace =
                this.Workspaces.FirstOrDefault(vm => vm is AllItemsViewModel)
                as AllItemsViewModel;

            if (workspace == null)
            {
                workspace = new AllItemsViewModel();
                this.Workspaces.Add(workspace);
            }

            this.SetActiveWorkspace(workspace);
        }