Edit markup element permission I'm using webforms on Drupal 8.5.1 . I want to add some custom, arbitrary text to the form, so I chose to add a markup element. We want to have the text at the top of the form "Thank you for taking the time to fill out this survey. In order to serve you better..." 

When the dialogue comes up, I see this:



From appearance and clicking, it seems like there is a missing textarea on the widget where I would enter the markup, right under the header "HTML markup". 

I'm not sure if this is a problem with my install, my settings, or perhaps a bug. 

I've looked at permissions and administrators have all webform permissions checked, and they are greyed out, so they can't be unselected. The account I'm using is an administrator account. 

I am new to Drupal 8, and even more so its webforms. Is there something wrong in my settings?
The missing editor is most likely a bug.  You should see what is being logged in the browser's JS console.

@see https://drupal.org/project/webform/issues/2936147