This appears to be exactly the issue I'm running into when setting OSXIsGUIApplication to true. The reason why I'd want this is that it fixes startup in non-bundled mode, i.e. -editor mode.
From what I can tell they're using similar-but-different hacks for moving the app into the foreground.
SDL uses a workaround: https://bugzilla.libsdl.org/show_bug.cgi?id=3051 (found also here ). WxWidgets appears to use another one...
That being said, I think the issue is that since we created an SDLApplication subclass of NSApplication, sharedApplication returns that (and not wxwidget's WXNsApplication), which breaks because apparently objective C can do fancy pointer checking.
It seems to be fundamentally broken on some level however, because we're subclassing in two different ways that are fundamentally incompatible.
I suspect the 'double-write' issue comes from there too, as we are probably getting the SDL hook instead of the wxwidgets one.
See doc:
https://developer.apple.com/documentation/appkit/nsapplication?language=objc
I must say I don't really see an easier fix than properly restarting atlas...