Form elements i.e. (radio, checkbox, text field, text area) are not editable and even can't be selected.

[rakin061]

Steps to reproduce

1. Open ​http://ckeditor.com/latest/samples/index.html on firefox 50.1.0 or some other latest versions in the newest version
2. Click radio, checkbox, text field, text area buttons and watch these are not working even these buttons can't be selected through clicking by mouse.

3.It works in Safari someway. Still in safari radio button is editable for one way. It means if the radio button has been selected then it can't be deselected again.

Expected result

These buttons should be editable like when using in simple html/js webpages. In fact, editing options are the main utility of these buttons.

Actual result

When selecting these buttons from toolbar these appears fine in the text area but are not editable.

I have explored about this issue and changed my plugin with 'formchanges' and 'nid_forms' plugins. But it didn't work.

Other details

(browser: Firefox 50.1.0 , OS: Windows 7 , CKEditor version 4.6.2, installed plugins: forms, formchanges, nid_forms)

[rakin061]

Image of my CKEditor Javascript version

[Jakub Ś]

DUP of #5804.