/// <summary>
        /// Expand folder for the very first time (using the process background viewmodel).
        /// </summary>
        /// <param name="expandedItem"></param>
        private void ExpandDummyFolder(IFolderViewModel expandedItem)
        {
            if (expandedItem != null && mIsExpanding == false)
            {
                if (expandedItem.ChildFolderIsDummy == true)
                {
                    mIsExpanding = true;

                    mExpandProcessor.StartProcess(() =>
                    {
                        expandedItem.ClearFolders();                    // Requery sub-folders of this item
                        (expandedItem as FolderViewModel).LoadFolders();

                        ////expandedItem.IsSelected = true;
                        ////SelectedFolder = expandedItem.FolderPath;
                    }, ExpandProcessinishedEvent, "This process is already running.");
                }
            }
        }