private void ShowAllGroups(ReadOnlyGroupList groups)
        {
            int groupsCount = groups.Count;

            for (int i = 0; i < groupsCount; i++)
            {
                Group group = groups[i];

                group.Visible = true;

                this.ShowAllGroups(group.Groups);
            }
        }
        private void ShowAllGroups(ReadOnlyGroupList groups)
        {
            int groupsCount = groups.Count;

            for (int i = 0; i < groupsCount; i++)
            {
                Group group = groups[i];

                group.Visible = true;

                this.ShowAllGroups(group.Groups);
            }
        }