but the simple silly home-made command which I was proposing also is fragile
Yes, I understand. I acknowledge that \MyFragileCmd above may be a bit out-of-scope Right. We don't want to get into \ifx. when \newcommand* is used to define a command with an optional argument, then it automatically robustify the command. Interesting. Probably we should also some day speak about robustification and indicate that \newcommand behaves this way. Yes. Is that something TeXLive does too ? Well, I didn't try it, but I'd be shocked if it was MiKTeX-specific. Surely this is done in the LaTeX code. Basically all that TL and MiKTeX do is redistribute it, not change it. -k