FULL PRODUCT VERSION :
java version "1.5.0_04"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_04-b05)
Java HotSpot(TM) Client VM (build 1.5.0_04-b05, mixed mode, sharing)


ADDITIONAL OS VERSION INFORMATION :
Linux 2.6.9-5.0.5EL (Scientific Linux4=RHEL4)

A DESCRIPTION OF THE PROBLEM :
When using the twm window manager, JComboBoxes are difficult to use.

You click on the JComboBox and the drop down menu appears - fine. However, if you subsequently move the mouse off of the button itself and onto the drop-down menu (or anywhere else) the dropdown menu disappears. The only way to make a selection is to keep the mouse button pressed down, in which case it is impossible to use the scroll bar.

This is a regression bug - at 1.4.2_08 you can move the mouse onto the drop down menu in twm with the button released and use the scroll bar as on other window managers (e.g. fvwm).

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
While running the twm window manager on Linux, create a GUI with a JComboBox in it,
display the JComboBox, click on it so the dropdown menu appears, release the mouse button, and try to grab the dropdown menu scrollbar.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
I wanted to be able to grab the scrollbar to make a selection.
ACTUAL -
The drop-down menu disappeared.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import javax.swing.JComboBox;
import javax.swing.JFrame;

public class C {
    public static void main( String[] args ) {
        JFrame f = new JFrame();
        f.getContentPane().add( new JComboBox( new String[] {
            "red", "blue", "green", "puce", "turquoise", "nymph's thigh",
            "yellow", "beige", "off-white", "off-black", "back-off",
        } ) );
        f.pack();
        f.setVisible( true );
    }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Keep the mouse button down and move the mouse above or below the drop-down menu which causes it to scroll up or down until the desired item is highlighted, then release the mouse button.

Or use another window manager.