Symptoms
After upgrading from 4.6.11 to 4.7, configuring a "Send an email" rule that previously worked now throws the error "Widget Error: Failed to execute 'evaluate' on 'Document' error'
Diagnoses
This is an issue when using a control with an apostrophe in the name in the email fields for the Send an Email rule.
Resolution
A bug has been logged for this behavior, introduced in 4.7. The workaround is to remove the apostrophe from the name of the control.