title: Java - Check Boxes in a JComboBox
body: <p>I would like to make a JComboBox that has check boxes for items instead of text. In addition, it should be possible to check multiple items and retrieve the selected items from the component. Should I be make a custom ComboBoxUI, ComboBoxEditor, ListCellRenderer, ComboPopUp, or something different entirely? Is there an existing Java control that does this?</p>