How to get radio boxes right in PDF forms using hyperref?

Question

I would like to create a fillable PDF form containing radio buttons using hyperref. The text fields turn out fine. The problem is with the radio boxes. Only one fillable radio box is visible when opened in evince and okular. Both boxes show up in skim and Preview on MacOS, but the checks are not saved (as opposed to the text fields).

(I am aware of the eforms package from the acrotex bundle, which makes the task easier, but forms created this way cannot be filled out by evince and okular.)

Here's my MWE:

\documentclass{article}
\usepackage{hyperref}

\def\LayoutTextField#1#2{\makebox[6em][l]{#1: }\raisebox{-.5ex}{#2}}
\def\LayoutChoiceField#1#2{\makebox[6em][l]{#1: }#2}
\newdimen\longline
\longline=\textwidth\advance\longline-6em

\begin{document}
\begin{Form}
\TextField[name=Name,width=\longline,borderwidth=0,bordersep=4pt,backgroundcolor={.85 .85 .85}]{Name}\vskip1ex

\TextField[name=Affiliation,width=\longline,borderwidth=0,backgroundcolor={.85 .85 .85},]{Affiliation}\vskip1ex

\ChoiceMenu[borderwidth=0,radio=true,backgroundcolor={.85 .85 .85}]{Are you a}{Student, Academic}\
\TextField[name=Comment,multiline=true,width=\longline,borderwidth=0,backgroundcolor={.85 .85 .85}]{Comments}\\
\end{Form}
\end{document}

What am I doing wrong with the radio boxes? Or is this an issue with the poppler library?