Correct name of macros?

I open the tex file with macros \newcommand{\ii}{\mathrm{i}}. In the texmacs it is shown as instead of definition. When I change the name of macros to \mathi : \newcommand{\mathi}{\mathrm{i}} it works well. Therefore, I can not use some names for macros?

I would guess there is some conflicts with macros in TeXmacs. But to be sure you would need to provide a reliable way to reproduce your findings. This will also ensure to you that you are correctly interpreting what is going on.

I really do not understand what’s going on. Today I decided make simple example and found that I can not reproduce this problem. I verified others my files with this definition and everything is ok. Sorry, it is mystic. There is another my post yesterday, where I reproduced the problem with another macros.

These are the famous Heisenberg bugs. When you look for them they disappear.