Make a JComboBox editable without affecting its width

Question

I have a JComboBox object in my JFrame which behaves exactly as expected. However, I'd like to make it editable so that users can input alternative values if necessary. Unfortunately, using setEditable(true) to enable editing causes its width to increase significantly. How can I allow editing of the JComboBox while keeping its width only as wide as the largest selectable item requires?

The JComboBox is in a JPanel with a FlowLayout, however I don't think this is relevant because changing the width of the JPanel does not affect the width of the JComboBox.

Answer 1

JComboBox@setPrototypeDisplayValue("XXXXXXXXXXXXXX")