Semantic Forms autocompletion, which currently uses jQuery UI Autocomplete, should switch to using the Select2 JS library (https://github.com/ivaynberg/select2). This will allow a number of important improvements:
- "Tokenization" of values (putting squares around each term), which has become increasingly common in user interfaces
- Flexible autocompletion for characters with accents
- Display of an image associated with each term
- Displaying values in a tree-type structure
- Much better support for autocompletion on remote data sets
Tied in with that, it may make sense to create a new input type, maybe called "tokens", that uses the standard Select2 handling for a field with a list of values. ("text with autocomplete" would possibly be deprecated as a result.) And "combobox" should switch to using Select2, and possibly become the default input type for Page property fields (replacing "text with autocomplete"). And possibly, but less likely, "combobox" and "tokens" should become the new default input types for enumerated fields holding a single and a list of values, respectively (replacing "dropdown" and "checkboxes").