private void categoriasToolStripMenuItem_Click(object sender, EventArgs e)
        {
            frm_categorias frm = new frm_categorias();

            frm.Show();
            this.Visible = false;
        }
        private void btnCadCat_Click(object sender, EventArgs e)
        {
            frm_categorias frm = new frm_categorias();

            frm.Show();
            this.Visible = false;
        }