I have seen several similar questions on TeX.SE of a similar nature, but none of them seem to address my precise issue. I have been working with mdframed environments for a while. I read that there were some issues with older versions, so I updated to the latest version, 1.9b, but it seems to have introduced a spacing issue that I did not have before.
\documentclass{article}
\usepackage{amsthm}
\usepackage{mdframed}
\theoremstyle{definition}
\newmdtheoremenv{definition}{Definition}
\begin{document}
\begin{definition}
This is a definition.
\end{definition}
\end{document}
The output, zoomed in, is seen here:

There is more vertical space above the contents than below. This only began after I fully updated my TeX distribution, so I assume that this possibly changed how mdframed works. Any ideas? Obviously I can manually change the spacing to fix this, but I'm looking to diagnose the problem, if there is one. Thanks in advance.


amsthmwas july 2009, and the last functional update was august 2004 (which, i believe, was beforemdframedeven existed), i seriously doubt that your updatingamsthmwas the cause of the recent change in your output. however, since this is a recognized deficit in the behavior ofamsthm + mdframed, it has been added to the list of requests for action whenamsthmand the ams document classes are next overhauled. – barbara beeton Mar 31 '14 at 14:07\listfilesmakes collecting this information easier, but if you don't have the ability to rerun an old attempt, that's not a particularly useful suggestion.) but if you could get that information, i'd be interested. – barbara beeton Mar 31 '14 at 20:02amsthm... – Christopher A. Wong Mar 31 '14 at 21:53-\topsepas well? Or rather, why is it not giving any trouble in the first place? – Fitzcarraldo Mar 18 '19 at 18:41