FULL PRODUCT VERSION :
java version "1.8.0_112"
Java(TM) SE Runtime Environment (build 1.8.0_112-b15)
Java HotSpot(TM) Client VM (build 25.112-b15, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 10.0.15063]

A DESCRIPTION OF THE PROBLEM :
When clicking the right-most pixel of a JComboBox the related Popup opens and closes immediately. Happens on any tested Look & Feel (Metal, Windows, Nimbus, BizLookAndFeel).

The problem seems located in BasicComboPopup.Handler.mouseReleased() :

    // ... more code
    Rectangle bounds = new Rectangle( 0, 0, size.width - 1, size.height - 1 );
    // ... more code

bounds' width and height shouldn't get reduced by one pixel.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Start SSCCE
2. Click on the right-most edge of the JComboBox
3. Watch the popup open and vanish again

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The Popup should stay open.
ACTUAL -
The popup closes again.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
package de.centigrade.bizlaf;

import java.awt.Container;
import java.awt.FlowLayout;

import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;

public class SSCCE {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new SSCCE().start();
            }
        });
    }

    public void start() {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Container contentPane = frame.getContentPane();
        JComboBox<String> comboBox = new JComboBox<String>(new String[] { "Item 1", "Item 2", "Item 3", "Item 4" });
        contentPane.setLayout(new FlowLayout());
        contentPane.add(comboBox);
        frame.setLocationRelativeTo(null);
        frame.pack();
        frame.setVisible(true);
    }
}
---------- END SOURCE ----------