Nested Modal Dialogs running on Mac OS can get wrong Z-Order

I have attached a sample creator app that exhibits the problem. The app has a main window and a button to launch a dialog. This is level one. Then that dialog launches a another dialog, which is level 2. Both dialogs are modal. The hierarchy is

Main Window
First Level
Second Level

Repro Steps:
On Mac OSX (10.9, but others should repro the same)
1. Launch the app. Click the first button and second button to get to the second level dialog.
2. Using the mouse, switch to a Finder window or another application.
3. Using the mouse, click on the first level dialog.

Expected:
The app activates, but the level 2 dialog is above the level 1 as it should be.

Actual:
The level 1 dialog will be above the level 2 dialog.