private void btnConfirm_Click(object sender, EventArgs e)
{
if (EchoInDisplay &&
_keyboardLayout == NumericKeyboardLayout.Decimal &&
!txtDisplay.IsEmpty &&
txtDisplay.Text.Trim().LastOrDefault() == '.')
{
txtDisplay.Text += "0";
}
UserConfirm?.Invoke(this, EventArgs.Empty);
ParentForm?.PerformConfirm(() => Text);
}