I'll let James comment and answer your specific questions, because he is the author of this component.
Please keep in mind that AutoCompleteSupport mimics the firefox address field as it were at that time, a few years back.
Because of backward compatibility reasons I think AutoCompleteSupport will stay more or less the same.
But if you want to contribute an alternative implementation/component, we'd appreciate it a lot.
If it turns out to be stable and useful, I'd be happy to include it in GlazedLists.
I am in the process of refactoring AutoCompleteSupport for my needs. I want to make it so, that it does not alter the editable property of the JComboBox any more but instead in readonly mode behaves more like the language selector at https://gist.github.com/. In editable mode it will behave as in non-strict mode.
I will remove strict and beepOnStrictViolation and any code handling these, because these are not necessary any more.
I want to drop any complexity from the editable combobox. The AutoCompletSupport wants to mimic the firefox address field. But firefox does not autocomplete, it just pops up a popup with suggestions. I think a lot of complexity can be dropped when the combobox behaves in editable mode exactly as the firefox address bar. The problem with the actual behavior is IMO with backspace. Backspace does behave strangely in non-strict mode.
What is the reason for isTableCellEditor? Why must we handle comboboxes differently when used as TableCellEditor?