Side navigation not working properly

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: Master
• Fix Version/s: 7.1.X, Master
• Component/s: Workflow > Portal > Configuration
• Labels:
  • fw_test_needed
  • smashing_march18
• Fix Priority: 4
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/56813

Steps to reproduce:

1. Go to Control Panel -> Configuration -> Workflow -> Single Approver
2. Click on info tab

Expected behavior:
Tab expands on the side showing content.

Actual behavior:
Error is throw on browser console
Uncaught TypeError: Cannot read property 'left' of undefined

Obs: The problem seems to be related with the initialization of var navigation on function showSidenav from js file side-navigation.js.
cc: clovis.neto