Using no-break spaces seems to break interaction between xcolor and ulem:
\documentclass{article}
\usepackage{xcolor}
\usepackage[normalem]{ulem}
\begin{document}
\textcolor{green}{\uline{\textcolor{blue}{TeX~StackExchange}}}
\end{document}
What's going on? I tried wrapping the last line in \traceon…\traceoff, but even just that line produced about 900 lines of output, and I don't know what to make of them. The problem exists both in XeLaTeX and pdfLaTeX.


\makebox[0pt][l]{\textcolor{blue}{\texttt{\coloruline{v}}}}\textcolor{blue}{\texttt{\uline{v}}}– Clément Aug 12 '16 at 01:19!; I tried adjusting the length of the\rule, but the "right" length for!is too short for, say,W, and vice versa) – Clément Aug 12 '16 at 01:25