How to have JComboBox drop down list which is wider than the JComboBox itself

Question

By referring to the answer at Multi Columns Combo Box for Swing, I manage to implement a 3 multi columns JComboBox as follow.

However, this is not perfect. My intention is to have something without the horizontal scroll bar, as follow.

My question is, how can I have a JComboBox drop down list, which is wider than the JComboBox itself? I just want to get rid of the horizontal scroll bar. Yet, able to fit in 3 columns into a single list.

The source code are ResultSetCellRenderer and AjaxAutoCompleteJComboBox

Answer 1

Try making custom.
Here is the code snippet

private static class PopupExpandingComboBoxUI extends WindowsComboBoxUI
{
protected ComboPopup createPopup()
{
return new ExpandingComboPopup(comboBox);
}
}
// Our custom popup menu - it makes up its own width
private static class ExpandingComboPopup extends BasicComboPopup
{
public ExpandingComboPopup(JComboBox cBox)
{
super(cBox);
}
public Rectangle computePopupBounds(int px, int py, int pw, int ph)
{
// Ok - just set the popup width to 200 for now - should be calculated though
return super.computePopupBounds(px, py, 200, ph);
}
}  

Source:http://www.thatsjava.com/java-programming/94874/

Answer 2

I got my problem resolved through the following forum Oracle Java Swing Forum

For future reference, I include the complete workable source code, for anyone who are interested.

AjaxAutoCompleteJComboBox.java