private void searchTextBox_TextChanged(object sender, EventArgs e)
        {
            string searchTerm = searchTextBox.Text;

            if (string.IsNullOrWhiteSpace(searchTerm))
            {
                backButton.Enabled = false;
                refreshMainForm();
                clearSearchResults();
                searchBoxLabel.Text = "Search Country:";
            }
            else
            {
                backButton.Enabled = true;
                clearAllInput();
                foreach (Country country in mainTree.GetCountries())
                {
                    if (country.Name.ToLower().StartsWith(searchTerm.ToLower().Trim()))
                    {
                        resultsTree.InsertItem(country);
                    }
                }
                foreach (Country result in resultsTree.GetCountries())
                {
                    if (!result.Name.ToLower().StartsWith(searchTerm.ToLower().Trim()))
                    {
                        resultsTree.RemoveItem(result);
                    }
                }
                countryList.DataSource    = resultsTree.GetCountries();
                countryList.DisplayMember = "name";
                searchBoxLabel.Text       = "Search Results: " + resultsTree.Count();
            }
        }
 private void deleteMenuItem_Click(object sender, EventArgs e)
 {
     if (MessageBox.Show("Do you want to remove " + selectedCountry.Name + " from the Main Tree?", "Delete Selected Country", MessageBoxButtons.YesNo, MessageBoxIcon.Warning) == DialogResult.Yes)
     {
         mainTree.RemoveItem(selectedCountry);
         refreshMainForm();
     }
 }