Make this editor full screen.

Describe the bug

While using the method toolbar.insertItem i am getting this error.

TypeError
this.el.appendChild is not a function

To Reproduce

Steps to reproduce the behavior:

1. Go to https://codesandbox.io/s/fragrant-hooks-gr651?file=/src/App.js:393-411 and https://github.com/nhn/tui.editor/issues/1245
2. See an error

Expected behavior

If I am returning the wrong value then, It should not rise this.el.appendChild is not a function. Because this. el is a class member. see this https://github.com/nhn/tui.editor/blob/3a0e0a93ae1970c2232060bf3ff747dd22413563/apps/editor/src/js/ui/uicontroller.js#L61.

If i am doing anything wrong then please suggest me.

[ats1999]

this worked

 const toggleEditorFullScreen = (el) =>{
    if(el.style.height !== "100vh")
      el.style = "height:100vh; width:100vw; position:fixed;z-index:10000000000;top:0px;left:0px;background-color:white;";
    else el.style = "height:400px;"
  }

[ats1999]

Now, i tried to give this styling to the root element.

Output

Problem

background contents are also visible in markdown mode(in preview part only). There is no problem in WYSIWYG mode.