OS X is complicated. Cocoa is a beast. As a result, windows
created using AWT/Swing are not properly registered with
the window management. Keyboard focus is difficult...

An application is not properly initialized as @NSApplication@,
thus the above mentioned quirks. If someone knows how to
properly and manually initialize a Cocoa application please
get in touch with me. The current workaround is in the function
@runCocoaMain@ in @src/ffijni.c@.