Thank you Chris, and apologies for the long delay! Let me build and check on my side.
So sorry about the long delay. I'm unsure why the library is not found - it does ship with the DMG and so ends up in folder /Applications/xmlcopyeditor. To fix the problem, I copied the library files in /Applications/xmlcopyeditor.app/Contents/Frameworks to /usr/local/lib. That's very far from a satisfactory solution of course.
[1.2.1.5-p2] fixed crash on Mac by switching to wxWidgets 3.1.3
Thanks for following up Earl! Can't promise an ETA for your excellent suggestion, but it makes perfect sense pinpointing the file that errored.
Font not sizeable
I'm interested in the size 4 default - I can't reproduce that at my end. I'm pretty sure it didn't do that on Windows last time I tried. I should rebuild anyway as the Mac port is one version (and lots of wxWidgets versions) ahead of master. Ctrl+U and Ctrl+D are unfortunate shortcuts - they were chosen because Ctrl++ and Ctrl+- weren't working correctly at the time (if I remember correctly - it's a little while ago).
removed wxDEBUG_LEVEL redefinition
applied clang-format