I am using the solution from How can I prevent a column break before the first sub-entry in the index? in my index. However, that has a bad side effect on the last page of the index in that the index entries on the left are vertically spaced:
How do I eliminate this excess spacing?
Code: A
\documentclass{article}
\usepackage{imakeidx}
%% Adapted from dapted from https://tex.stackexchange.com/q/130169/4301
\makeatletter
% we don't want a page break before a subitem
\renewcommand\subitem{@idxitem\nobreak\hspace*{20\p@}}
\makeatother
\makeindex
\begin{document}
Some text
\index{gap!radial}\index{gap!axial}
\index{gapa!radial}\index{gapa!axial}
\index{gapb!radial}\index{gapb!axial}
\index{gapc!radial}\index{gapc!axial}
\index{gapd!radial}\index{gapd!axial}
\index{gap1!radial}\index{gap1!axial}
\index{gapa1!radial}\index{gapa1!axial}
\index{gapb1!radial}\index{gapb1!axial}
\index{gapc1!radial}\index{gapc1!axial}
\index{gapd1!radial}\index{gapd1!axial}
\index{gap2!radial}\index{gap2!axial}
\index{gapa2!radial}\index{gapa2!axial}
\index{gapb2!radial}\index{gapb2!axial}
\index{gapc2!radial}\index{gapc2!axial}
\index{gapd2!radial}\index{gapd2!axial}
\index{gap2!radial 1}\index{gap2!axial 1}
\index{gapa2!radial 1}\index{gapa2!axial 1}
\index{gapb2!radial 1}\index{gapb2!axial 1}
\index{gapc2!radial 1}\index{gapc2!axial 1}
\index{gapd2!radial 1}\index{gapd2!axial 1}
\index{gap2!radial 2}\index{gap2!axial 2}
\index{gapa2!radial 2}\index{gapa2!axial 2}
\index{gapb2!radial 2}\index{gapb2!axial 2}
\index{gapc2!radial 2}\index{gapc2!axial 2}
\index{gapd2!radial 2}\index{gapd2!axial 2}
\index{gap2!radial 3}\index{gap2!axial 3}
\index{gapa2!radial 3}\index{gapa2!axial 3}
\index{gapb2!radial 3}\index{gapb2!axial 3}
\index{gapc2!radial 3}\index{gapc2!axial 3}
\index{gapd2!radial 3}\index{gapd2!axial 3}
\index{gap2!radial 4}\index{gap2!axial 4}
\index{gapa2!radial 4}\index{gapa2!axial 4}
\index{gapb2!radial 4}\index{gapb2!axial 4}
\index{gapc2!radial 4}\index{gapc2!axial 4}
\index{gapd2!radial 4}\index{gapd2!axial 4}
\index{gap2!radial 5}\index{gap2!axial 5}
\index{gapa2!radial 5}\index{gapa2!axial 5}
\index{gapb2!radial 5}\index{gapb2!axial 5}
\index{gapc2!radial 5}\index{gapc2!axial 5}
\index{gapd2!radial 5}\index{gapd2!axial 5}
\index{gap2!radial 6}\index{gap2!axial 6}
\index{gapa2!radial 6}\index{gapa2!axial 6}
\index{gapb2!radial 6}\index{gapb2!axial 6}
\index{gapc2!radial 6}\index{gapc2!axial 6}
\index{gapd2!radial 6}\index{gapd2!axial 6}
\printindex
\end{document}

\raggedcolumns\printindex? – David Carlisle Sep 23 '19 at 20:54\usepackage[unbalanced=true]{idxlayout}in the preamble. It depends on how many entries there are on the last page. If there are only ten or twelve, this would be ok (for me, at least!). – Kubo Jul 20 '20 at 00:35