da meine Demo von PlistEditPro abgelaufen ist, habe ich mich noch mal an Proper Tree rangemacht, die Lösung ist da:
Fürs Archiv:
ProperTree opens a black window on macOS Monterey (12.x)
It appears the default tk implementation that ships with macOS Monterey doesn't display correctly. A workaround is to download and install python from python.org (which has a compatible tk bundled), then use the buildapp-select.command
located in ProperTree's Scripts
directory to build an application bundle targeting the installed python's path.