Let's suppose we have 2 frames and one ownerless APPLICATION_MODAL dialog.
On X Window, if you minimize one of the frames, the dialog will minimize with it. If both frames are minimized and you restore either of them, dialog will restore as well.

Now, on Mac all three windows are completely independent in that regard. You may minimize and restore them in any combination at will, independently. Frames are blocked, however, which is someway confusing if a blocking dialog is minimized.

As an example, see the test mentioned in the Comments.