It's all in the subject.
I used all kinds of boxes in a towcolumn article, but whenever the boxed text is long enough, the box happily continues into the other column!
Is there a "smart" box that "follows" the text, like the blue one aroung URLs ? Sample document:
\documentclass[10pt,twoside,twocolumn,english]{article}
\begin{document}
\fbox{Alpha particles (named after and denoted by the first letter in the
Greek alphabet) consist of two protons and two neutrons bound
together.
This means that an particle is a helium nucleus. }
\end{document}



\mboxis indivisible by design. – egreg Jun 09 '12 at 10:45