What is wrong with this if combobox selectedtext statement?

The combobox "PanelAddComboBoxCurrency" is selected to GBP so it when typing numbers into it it should populate some other textboxes, doesnt seem to work though?


private void PanelAddTextBoxSubTotal_Leave(object sender, EventArgs e)
        {
            if (PanelAddTextBoxSubTotal.Text == "")
            {
            }
            else if(PanelAddComboBoxCurrency.SelectedText == "GBP")
            {
                double Subtotal = Convert.ToDouble(PanelAddTextBoxSubTotal.Text);
                double VAT = (Subtotal / 100 * 17.5);
                double Total = (Subtotal + VAT);

                PanelAddTextBoxVAT.Text = Convert.ToString(VAT);
                PanelAddTextBoxTotal.Text = Convert.ToString(Total);
            }
        }