Reproducible: Always
Is a regression: No
Is a platform-specific: Yes (Mac only)

Steps to reproduce (run attached file).
1. Create dialog without parent.
2. Create dialog with root dialog as a parent
3. Set modality exclusion to APPLICATION_EXCLUDE for the root
4. Create native modal dialog (e.g. printer dialog)
Expected behaviour (as on Windows, Xorg): none of the dialogs are blocked by modal printer window
Actual behaviour: child windows are blocked by printer dialog, only root dialog is accessible.