It's a wxWidgets-bug.
I don't know at the moment whether a workaround exists or not.
Might depend on your wxWidgets version.
What you can try, is to backup your
default.conf on Mac and edit it manually.
Inside the
<editor> ... </editor> tags, there should be
<FONT> section, that can be edited.
On newly created default.conf's it's most likely not there, but you can try to add it manually.
On my debian-system it looks like (default-settings after opening the font-choser and closing it):
<FONT>
<str>
<![CDATA[Monospace 10]]>
</str>
</FONT>
I don't know whether it's a valid font-description on Mac, but I think it might be a starting point.
(Obviously the
10 is the font-size in points.)
But as told at the beginning: please backup your
default.conf (at least if you have made any important changes), because editing it manually can always lead to errors !