private void groupListView_DoubleClick(object sender, EventArgs e)
        {
            // get the selected group name
            string groupName = groupListView.SelectedItems[0].Text;

            // set up the selected ContactGroup group
            ContactGroup contactGroup = null;

            foreach (ContactGroup group in GroupList)
            {
                if (group.Name.Equals(groupName))
                {
                    contactGroup = group;
                    break;
                }
            }

            // open a CreateGroupForm
            CreateGroupForm groupForm = new CreateGroupForm(contactGroup);

            groupForm.ShowDialog();
        }
        private void createGroupButton_Click(object sender, EventArgs e)
        {
            CreateGroupForm groupForm = new CreateGroupForm(null);

            groupForm.ShowDialog();
        }