Description
After changing the key signature of one file, I switched to a file in another tab and clicked on "Edit Key Signature...".
Usually the "Edit Key Signature..." menu item is greyed out, unless you click somewhere on the tab lines.
In this case the menu item was not greyed out, even though i hadn't selected anything, so when I clicked on "Edit Key Signature..." the program crashed. Now every time I try to open Power Tab Editor, it immediately crashes and throws the following error message:

Unhandled exception: Unknown object type. 0# main in /Applications/Power Tab Editor.app/Contents/MacOS/Power Tab Editor
 1# main in /Applications/Power Tab Editor.app/Contents/MacOS/Power Tab Editor
 2# std::__terminate(void (*)()) in /usr/lib/libc++abi.dylib
 3# __cxa_get_exception_ptr in /usr/lib/libc++abi.dylib
 4# __cxxabiv1::failed_throw(__cxxabiv1::__cxa_exception*) in /usr/lib/libc++abi.dylib
 5# SettingsTree::loadFromPlist() in /Applications/Power Tab Editor.app/Contents/MacOS/Power Tab Editor
 6# SettingsTree::loadFromPlist() in /Applications/Power Tab Editor.app/Contents/MacOS/Power Tab Editor
 7# SettingsManager::load(std::__1::__fs::filesystem::path const&) in /Applications/Power Tab Editor.app/Contents/MacOS/Power Tab Editor
 8# main in /Applications/Power Tab Editor.app/Contents/MacOS/Power Tab Editor
 9# start in /usr/lib/dyld

I even tried deleting and reinstalling the app, as well as deleting the "powertab" directory in "Application Support", but the programm still crashes and throws the same error.

To Reproduce

• Have 2 files open
• Edit the key signatue in one file
• Switch to the other file, that is in a state that usually would not allow you to edit the key signature
• Try to edit it anyway because the menu item isn't greyed out

Version
MacOS 15.0, Power Tab Editor Alpha 19