[Tex/LaTex] Force itemize inside description onto a new line

Question

I have an itemize inside a description, like this:

\documentclass[]{article}
\usepackage[vmargin=1in,hmargin=1in]{geometry}
\usepackage{enumitem}
\setlist[description]{style=nextline}

\begin{document}

\begin{description}
  \item[Definition 1]
  \begin{itemize}
    \item One
    \item Two
    \item Three
  \end{itemize}
  \item[Definition 2]
  \begin{itemize}
    \item Four
    \item Five
  \end{itemize}
\end{description}

\end{document}

However, despite the style=newline (which works for normal text in a description item), the first item of the itemize is on the same line as the definition:

How can I force the itemize to begin on a new line?

Ideally, I am looking for a solution I can put in an options.sty rather than an in-line solution involving mboxes etc. (the actual latex causing me a problem is being generated from reStructuredText via pandoc, however the snippet above reproduces the problem).

Answer 1

You could try some variation on the following:

\documentclass[]{article}
\usepackage[vmargin=1in,hmargin=1in]{geometry}
\usepackage{enumitem}
\setlist[itemize]{topsep=0pt,before=\leavevmode\vspace{-1.5em}}
\setlist[description]{style=nextline}
\begin{document}

\begin{description}
  \item[Definition 1]
  \begin{itemize}
    \item One
    \item Two
    \item Three
  \end{itemize}
  \item[Definition 2]
  \begin{itemize}
    \item Four
    \item Five
  \end{itemize}
  \item[Definition 3]
  This is a normal description.
\end{description}
\end{document}

This important bit is the \setlist[itemize]{...}. This gives: