Chocolat mixin onUnload does not fire when window is closed using the red "X"

init.js

//
// To test:
//
// (Use this in a Chocolat Mixin. Drop in any default.html file.)
//
// 1. Press Cmd-Opt-Ctrl-H and note the window appears.
// 2. Press "OK" and note that onUnload fires.
// 3. Repeat several times until you're convinced it works.
//
// Then:
//
// 4. Press Cmd-Opt-Ctrl-H. The window will appear.
// 5. Close the window using the red "X" in the corner. Note that
//    onUnload does not fire.
// 6. Press Cmd-Opt-Ctrl-H. The window will *probably* appear.
// 7. Close it again using the red "X".
// 8. Open again and close using the red "X". After the second or
//    third time it no longer works.
//
// Hypothesis: Closing the window with the red "X" deallocates it.
// When it's re-opened, we are seeing a window that has been or is
// about to be deallocated. It just happens to work--at first.
//
// Problem: Without a way to detect if the window exists or has been
// deallocated, it's hard to have a clean UI for mixins like JSHint.
//

// global, so we can try to re-use the window
var win;

Hooks.addMenuItem('Actions/JavaScript/Testing 1 2 3', 'cmd-opt-ctrl-h', function() {
	if (win === undefined) {
		win = new Window();
		win.htmlPath = 'default.html';
		
		win.onUnload = function() {
			Alert.show('debug', 'onUnload', ['OK']);
			win = undefined;
		};
		
		win.buttons = ["OK"];
		win.onButtonClick = function() {
			// Note: onUnload will be fired.
			win.close();
		};

		win.run();
	} else {
		// this may work one or two times, but then it will fail
		win.show();
	}
	
});

Also, win.isVisible() will eventually return false but calling win.show() does not show it. Because the window has been deallocated?