bugfix: the DnD handler does not EXIT_ON_CLOSE

which was closing the parent process, closing also
the main Fiji window

this was a left over from the /src/test/.. times where
Vlado was starting Mastodon directly from IDE and closing the
Mastodon window wasn't closing the process making IDE believe
that the program is still running

Author: xulman

src/main/java/org/mastodon/mamut/launcher/MastodonDndLauncher.java

@@ -68,12 +68,16 @@ public Object open(Location source) throws IOException {
 
 		final String projectPath = fsource.getFile().getAbsolutePath();
 
+		//make sure that the menus appear on top of the screen
+		//to look natively in the Apple world
 		System.setProperty( "apple.laf.useScreenMenuBar", "true" );
+
+		//start up "the main object behind the scenes" -- the WindowManager,
 		final WindowManager windowManager = new WindowManager( getContext() );
 
+		//start up the main/central Mastodon window
 		final MainWindow mainWindow = new MainWindow( windowManager );
 		mainWindow.setVisible( true );
-		mainWindow.setDefaultCloseOperation( WindowConstants.EXIT_ON_CLOSE );
 
 		try {
 			final MamutProject project = new MamutProjectIO().load( projectPath );