private void btnThemNhaCungCap_Click(object sender, EventArgs e) { FrmNhaCungCap frmNhaCungCap = FrmNhaCungCap.Instance; frmNhaCungCap.MinimizeBox = false; frmNhaCungCap.FormClosed += FrmNhaCungCap_FormClosed; ((FrmMain)this.ParentForm).TopMost = false; frmNhaCungCap.ShowDialog(); }