private void Initialize_Boxes()
        {
            // ID textbox defaultna ("autoincrement") vrijednost
            sql     = "SELECT MAX(ID) FROM Companies;";
            number  = Convert.ToInt32(m_database.Get_Single_Data(sql));
            ID.Text = (++number).ToString();

            Ime_Firme.Text = "";
            OIB.Text       = "";
            Adresa.Text    = "";

            m_unos.Remove("ID");
            m_unos.Remove("name");
            m_unos.Remove("OIB");
            m_unos.Remove("adresa");
        }