Currently the spec for JComboBox.processKeyEvent() is following:
"Handles KeyEvents, looking for the Tab key. If the Tab key is found, the popup window is closed."
But the key to close popup window should be current L&F dependent. Here it's hardcoded for all L&Fs. Is it intentional to preserve this TAB dependency to close popup?
It'll be useful to remove such TAB dependency in processKeyEvent() method and make it really L&F dependent.