Labeling diagonal arrows with the diagrams package

Question

As far as I can tell, the following code

\usepackage[balance,small]{diagrams}

...

\begin{diagram}
&& X && \\
& \ldTo^\Phi & & \rdTo^\Psi &\\
Y &&&& Z
\end{diagram}

should produce a diagram with diagonal arrows and labels which are horizontal (i.e. not slanted with the arrows), at least that's what happens in Milne's documentation (http://www.jmilne.org/not/Mdiagrams.pdf). However my labels (Phi and Psi) are slanted along the arrow.

How do I make it so the labels are horizontal?

Answer 1

Including the option [nohug] will make it so that labels do not slant with the arrow. The top line should be:

\usepackage[balance,small,nohug]{diagrams}