List ribbon not load issue in Office 365

Issue:
Recently, we have a strange issue. The list was not showing ribbon tabs default. There are many reasons I found for this behavior, like

• Permission issue - we have site collection access
• custom script to stop ribbon load - we have checked there was no custom coding done.

Then we found a blog stating that even if you add any custom webpart in list / library page, the ribbon lost its focus from main webpart. So it won't show. Andd it was true. we have added a legal text in our list heading using content editor webpart.

Solution:

So what is solution to bring it back? Below is code sample that we added in our page for loading ribbon tab on page load.

Code:
window.onload = function(){
  var elem = document.getElementById("MSOZoneCell_WebPartWPQ2");
  if (elem != null) {
      var dummyevent = new Array();
      dummyevent["target"] = elem;
      dummyevent["srcElement"] = elem;
      elem.parentNode.click();
      WpClick(dummyevent);
   }
//code to click browse button
   document.getElementsByClassName("ms-cui-tt-span")[0].click();
   }