Error thrown when pressing a "select all" button in a source view

[Mgsy]

Are you reporting a feature or a bug?

Bug

Provide detailed reproduction steps (if any)

1. Open a sample.
2. Switch to the source view.
3. Press "Select all" button.

Expected result

Action should select whole editor's content.

Actual result

Exception is thrown:
SCRIPT438: Object doesn't support property or method 'createTextRange'
ckeditor.js (1065,311)

Other details

• Browser: Edge
• OS: Windows 10
• CKEditor version: 4.7.1