Issue with glossaries and hierarchal categories

Question

I'm having an issue using the hierarchal categories feature for the glossaries package. What i'm trying to do is add various entries under the "Greek Letters" parent. First, without adding the parent option to a glossary entry I get the following:

So far, so good. Now, if I add the parent option to the delta and pi glossary entries I get the following:

As you can see, the entries are combined into one instead of on three lines with "Greek letters" entry first.

Here is the code to produce the two cases:

%% no parent option
\documentclass[12pt,letterpaper]{report}
\usepackage[nonumberlist,toc,nopostdot]{glossaries} % load after hyperref
\makenoidxglossaries
\newglossaryentry{greekletter}{name={Greek letters},description={\glspar}}
\newglossaryentry{pi}
{
  name={\ensuremath{\pi}},
  sort={pi},
  description={ratio of the circumference of a circle to the diameter}
}
\newglossaryentry{delta}
{
  name={\ensuremath{\delta}},
  sort={delta},
  description={change in ...}
}

\begin{document}
  \glsaddall
  \printnoidxglossary
\end{document}

%% parent option
\documentclass[12pt,letterpaper]{report}
\usepackage[nonumberlist,toc,nopostdot]{glossaries} % load after hyperref
\makenoidxglossaries
\newglossaryentry{greekletter}{name={Greek letters},description={\glspar}}
\newglossaryentry{pi}
{
  name={\ensuremath{\pi}},
  sort={pi},
  description={ratio of the circumference of a circle to the diameter},
  parent=greekletter
}
\newglossaryentry{delta}
{
  name={\ensuremath{\delta}},
  sort={delta},
  description={change in ...},
  parent=greekletter
}

\begin{document}
  \glsaddall
  \printnoidxglossary
\end{document}

Answer 1

You need to use a style that supports hierarchical entries, such as one of the tree or index styles. (See the table in the Predefined Styles section of the glossaries user guide. Choose one that doesn't have a check mark in the "Homograph" column.)

\documentclass[12pt,letterpaper]{report}

\usepackage[nonumberlist,toc,nopostdot,style=tree]{glossaries}

\makenoidxglossaries

\newglossaryentry{greekletter}{name={Greek
letters},description={\glspar}}
\newglossaryentry{pi}
{
  name={\ensuremath{\pi}},
  sort={pi},
  description={ratio of the circumference of a circle to the
diameter},
  parent=greekletter
}
\newglossaryentry{delta}
{
  name={\ensuremath{\delta}},
  sort={delta},
  description={change in ...},
  parent=greekletter
}


\begin{document}
  Test.

  \glsaddall
  \printnoidxglossary
\end{document}

This produces: