Not able to add new product into order or deal

• Description of the problem
• Solution

Description of the problem

Not able to add a new product into a deal (Contacts plugin) or order (Products plugin), the error while typing is:

new:261 Uncaught ReferenceError: add_fields is not defined
at HTMLAnchorElement.onclick (new:261:3748)
onclick @ new:261

Solution

Please execute the following command to fix the problem:

bundle exec rake assets:precompile RAILS_ENV="production" 

Important: Please note that the problem appears mostly on Redmine 6+.