The support for “apple.awt.documentModalSheet” property implemented under JDK-8208543 is incomplete. The window with the property “apple.awt.documentModalSheet” set to Boolean.TRUE is not attached to its owner.

Test case to reproduce the issue:

import javax.swing.JDialog;
import javax.swing.JFrame;
import java.awt.Dialog;
import javax.swing.JLabel;

public class DocumentModalSheet {
    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setSize(300,300);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
        JDialog dialog =
                new JDialog(frame, null, Dialog.ModalityType.DOCUMENT_MODAL);
        dialog.getRootPane().putClientProperty("apple.awt.documentModalSheet",
                                               Boolean.TRUE);
        dialog.add(new JLabel("Hello world!"));
        dialog.pack();
        dialog.setVisible(true);
    }
}

Expected result:
The dialog appears as a sheet attached to the owner

Actual result:
The dialog appears as a sheet but is not attached to the owner and located at the upper-left corner of the screen