How prevent overwrite of theorem-like head when showkeys loaded?

Question

The following source causes the "EXERCSISES" head in the theorem-like environment to be overwritten with the 1st item of the enumerated list inside:

\documentclass{article}

\usepackage{amsthm}
\usepackage{thmtools}
\usepackage{enumitem}

\declaretheoremstyle[
headfont=\bfseries,%
headpunct={\vspace{\topsep}\newline},
numbered=no,
spaceabove=3\topsep,
postheadspace=0 pt ]{exercs}

\declaretheorem[name=EXERCISES,style=exercs]{problems}

\newlist{problemsenum}{enumerate}{3}
\setlist[problemsenum,1]{%
    label=\arabic*.,
    before=\leavevmode \vspace{-\dimexpr\baselineskip+\topsep\relax}
}

\usepackage{showkeys} 

\begin{document}

\begin{problems}
\label{myproblems}

\begin{problemsenum}

\item Do this one first.
\item Solve this next.

\end{problemsenum}

\end{problems}

\end{document} 

Commenting out the \usepackage{showkeys} or omitting the \label prevents the overwriting:

Is there some way to prevent the overwriting even with showkeys loaded and with the \label still included?

One way to prevent the overwriting when showkeys is not loaded is simply to remove the newline between \begin{problems} and the \label command:

\begin{problems}%
\label{my problems}

However, even with that change, once showkeys is loaded the overwriting persists. Hence a more robust workaround would be desirable.

Note: The seemingly convoluted definition of the problemsenum environment is needed in order to be able to create cross-references to individual items in the problemsenum environment, with \cref, even though the theorem-like environment is unnumbered. (See How use cleveref to get theorem-like name and list item number? and How change vertical space after head in theorem-like environment .)

Answer 1

Packages like showkeys work at a quite deep level and make some assumptions about how certain things such as theorem labels are produced. In this case, your abuse of headpunct for inserting a \vspace confuses showkeys.

It turns out that the competitor in the field works for this special case:

\usepackage{showlabels}

This package is even more customizable than showkeys, so my advice is to switch. However, there's no guarantee that other complicated things like those you do here will work. In any case, both showkeys and showlabels are only used during the writing of the document, where some poor typesetting can be ignored.