void (@NotNull Window window) { myListener = new FullScreenListener() { @Override public void windowEnteringFullScreen(FullScreenEvent event) { myIsFullScreen = true; } @Override public void windowEnteredFullScreen(FullScreenEvent event) { myIsFullScreen = true; } @Override public void windowExitingFullScreen(FullScreenEvent event) { myIsFullScreen = false; } @Override public void windowExitedFullScreen(FullScreenEvent event) { myIsFullScreen = false; } }; FullScreenUtilities.addFullScreenListenerTo(window, myListener); }