Bookmarks are created inside filler

[Comandeer]

Type of report

Bug

Provide detailed reproduction steps (if any)

1. Open https://jsfiddle.net/Comandeer/yecqv9po/
2. Open console.
3. Select all content inside the editor.
4. Click button below the editor.

Expected result

There is no error inside the console.

Actual result

There is error inside the console:

Uncaught TypeError: Cannot read property 'getParent' of null
    at CKEDITOR.dom.range.setStartBefore (ckeditor.js:181)
    at CKEDITOR.dom.range.moveToBookmark (ckeditor.js:164)
    at CKEDITOR.dom.selection.selectBookmarks (ckeditor.js:486)
    at CKEDITOR.dom.element.<anonymous> ((index):46)
    at CKEDITOR.dom.element.l (ckeditor.js:10)
    at CKEDITOR.dom.element.fire (ckeditor.js:12)
    at HTMLButtonElement.<anonymous> (ckeditor.js:72)

Other details

After selecting all content, widgetselection creates temporal div at the beginning of the content, which is deleted when selection is changed. However Chrome and Safari creates start bookmark inside this temporal element. When selection changes, div is deleted with a bookmark inside it, causing an error when then trying to select bookmarks.

The issue is present in 4.8.0+ even if there are no widgets inside the editor, due to the fact that uploadimage is a default part of presets and it requires widgetselection.

• Browser: Chrome, Safari
• CKEditor version: 4.8.0+
• Installed CKEditor plugins: widgetselection