Fix Workflow Tasks buttons display in a given session

If user has accessed the Workflow tab for a document at least once in the session, if new tasks are assigned the display is incorrect (e.g. buttons missing). In 5.9.6 the assignee's can be missing as well.

Steps to reproduce

• You can use http://demo.nuxeo.com.
• Browser1: Log in as Administrator.
• Browser2: Log in as Bill.

IMPORTANT: do not switch users by logging out and logging in. Use two browsers or Chrome's multiuser feature for example.

• Browser1:
  • Open Default domain > Workspaces > IT Department > Compte-rendu réunion du mois
  • Start the "Serial Document Review" workflow.
  • Open the Workflow tab.
  • Add Bill as a Participant.
  • Set "Validation or simple review" to "Simple review".
  • Click "Start the review".
• Browser2:
  • Open Default domain > Workspaces > IT Department > Compte-rendu réunion du mois
  • Open the Workflow tab.
  • Click "Reject".
  • (This assigns the task back to Administrator).

(note in 5.9.6 the assignee is missing)

• Browser1:
  • Refresh the page.
  • (you should already be on the Workflow tab).

Result: the buttons for the Workflow task are missing.
(note in 5.9.6 the assignee is also missing)

• Browser1:
  • Select the folder ("IT Department").
  • Select the document ("Compte-rendu réunion du mois").
  • Open the Workflow tab.

Result: the buttons for the Workflow task are missing.
(note in 5.9.6 the assignee is also missing)

Workaround1

• Browser1:
  • Open "Home".
  • Select "Dashboard".
  • Locate the task ("Update the document" > "Compte-rendu réunion du mois") and click the link.
  • Open the Workflow tab.

Result: the buttons for the Workflow task are NOT missing.

Workaround2

Logout and log back in.