Stormshadow Stormshadow - 1 year ago 72
Java Question

How to keep the popup menu of a JComboBox open on populating it?

I have a JComboBox on my Panel. One of the popup menu items is 'More' and when I click that I fetch more menu items and add them to the existing list. After this, I wish to keep the popup menu open so that the user realizes that more items have been fetched however, the popup closes. The event handler code I am using is as follows

public void actionPerformed(ActionEvent e)
if (e.getSource() == myCombo) {
JComboBox selectedBox = (JComboBox) e.getSource();
String item = (String) selectedBox.getSelectedItem();
if (item.toLowerCase().equals("more")) {

private void fetchItems(JComboBox box)
/* code to fetch items and store them in the Set<String> items */
for (String s : items) {

I do not understand why the showPopup() and setPopupVisible() methods are not functioning as expected.

Answer Source

add the following line in the fetchItems method

SwingUtilities.invokeLater(new Runnable(){

    public void run()



If u call selectedBox.showPopup(); inside invokelater also it will work.

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