Mantis plugin add custom fields with autocomplete feature (dropdown menu) and separated config for each project that has a field added to it.
Simple copy CustomFieldsAutocomplete folder into mantis/plugins directory and enable in plugin management page
- Create custom field with type "Custom field with autocomplete"
- Add created field to project
- Set default values for field in project edit page separated by '|' like 'Enumeration' custom field
- Enjoy.