APEX: Show error messages in UI triggered by 'After Undelete' trigger
Under Point Threshold
If an error message is added to a record in an 'after undelete' APEX trigger, the error message is not displayed to the user. This behavior is dissimilar to how the 'addError()' method works in other trigger types. Instead, the user encounters a generic error message. Please allow us to display the reason we are interrupting the undelete, so we can properly instruct our users how to handle this case.