I just want to share a solution to a problem, which had been driving me mad for some time.
I've benn using Lyx for a while, when I came across a neat package called chemfig, which is great for chemical diagrams. Unfortunatly, some of its features, which was using parentesis arguments were unavalible - the code won't compile:
\documentclass[oneside,czech]{book} \usepackage{babel} \usepackage{chemfig} \begin{document} \schemestart A \arrow(aa--bb) B \schemestop \end{document}
Error:
! Paragraph ended before \CF@arrow@i was complete.
It took me a while to find out what is causing this problem: Babel and its shorthnads. According to the babel documentation, there's a hypen (-) defined as shorthand character. This applies by default to Czech and Slovak languages. Therefore babel misinterprets chemfig arguments and the command seems to be unfinished (at least I think so

The solution si quite simple: use babel commands to turn off the shorthand teporarily for the chemfig block:
\documentclass[oneside,czech]{book} \usepackage{babel} \usepackage{chemfig} \begin{document} \shorthandoff{-} \schemestart A \arrow(aa--bb) B \schemestop \shorthandon{-} \end{document}
Works like a charm

Because I'm new to LaTeX, please excuse the crudeness of my solution. I just wanted to help those with similar problem. If there is a better/more elegant solution, I would be pleased to see it.