Fix the Approve button in a standalone task

When clicking on the Approve button, we get redirected to the domain view.
Looking at the browser console, there is a Javascript error

Uncaught TypeError: Cannot set property 'adp' of null
  apf @ jsf.js.faces?ln=javax.faces:1jsfcljs @ 
  jsf.js.faces?ln=javax.faces:1
  onclick @ doc 2@view_documents?tabIds=%3A&conversationId=0NXMAIN8:2337

There is a difference between the Approve and Reject buttons : Approve uses a h:commandLink whereas Reject uses a a4j:commandLink