Question

I have a simple JComboBox

JComboBox comboBox = new JComboBox();
comboBox.setModel(new DefaultComboBoxModel(new String[] {"foo", "bar"}));

In some cases the arrow keys work for the list traversal in the popup. But in certain cases the arrow keys do not work(no exceptions are raised in these cases).

I have narrowed down to the cases when the arrow keys do not work.

I wanted to know what could lead to the arrow keys not working so that I could limit my focus area. I am sorry but I cannot provide the SSCCE for this problem.

Answer 1

I had removed the ActionMap for the arrow key in my custom autocomplete combobox which extends JComboBox

getActionMap().getParent().remove("selectNext");

I had not reset the action keys when the user entered some value not in the list and moved on. This lead to all the JComboboxes in the application to stop responding to the arrow keys.

I had initially saved the action for the selectNext and reset the action at the error incidence mentioned above to get the code working

Action selectNextAction = getActionMap().getParent().get("selectNext");
//...
getActionMap().getParent().put("selectNext", selectNextAction);