Data Object source modify retains validation error

1. Created new Data Object using editor
2. In source view of data object, added method ("addCode") to add item to field that is a List
3. Error though during validation.
4. Removed added method and saved.
5. Validation error remained "Rule Compilation error addCode cannot be resolved or is not a field"
6. Deleted data object
7. Added fields in editor
8. Validation error remained for "addCode" where there is no "addCode" in the entire repository anymore.