ADDITIONAL SYSTEM INFORMATION :
java version "10.0.1" 2018-04-17
Java(TM) SE Runtime Environment 18.3 (build 10.0.1+10)
Java HotSpot(TM) 64-Bit Server VM 18.3 (build 10.0.1+10, mixed mode)
macOS Sierra 10.12.6

Issue appears in other tested versions osx 10.9.5+
Also occurs in JDK 8u171

A DESCRIPTION OF THE PROBLEM :
If you have nested panels in a Java application and a Window Manager app active (Magnet, Moom, SnapIt) any click on/focus event from the lower components causes the Java application to hang

REGRESSION : Last worked in version 10.0.1

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Install and enable a Window manager app, SnapIt is free
Run the code below

Note: if using JDK 8 increase the panel depth to 20 to see full hang without recovery, depth of 10 will recover after a while

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Can click on the component without application hang
ACTUAL -
Application hangs

---------- BEGIN SOURCE ----------
import javax.swing.*;
import java.awt.*;

public class Main {

    public static void main(String[] args) {
        final JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(new Dimension(400,400));

        final Container content = frame.getContentPane();
        content.setLayout(new BorderLayout());
        
        Container lastPanel = content;
        for (int i = 0; i < 10; i++) {
            final JPanel p = new JPanel();
            lastPanel.add(p);
            lastPanel = p;
        }
        lastPanel.setBackground(Color.blue);
 
        frame.setVisible(true);
    }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Disable the Windows Manager app in the System Accessibility options

FREQUENCY : always