src/vs/workbench/browser/parts/views/viewPane.ts/ViewWelcomeController/contents
class ViewWelcomeController:	get contents(): IViewContentDescriptor[] {
		const visibleItems = this.items.filter(v => v.visible);

		if (visibleItems.length === 0 && this.defaultItem) {
			return [this.defaultItem.descriptor];
		}

		return visibleItems.map(v => v.descriptor);
	}