Are you reporting a feature or a bug?

Bug

Check if the issue is already reported

http://dev.ckeditor.com/ticket/14291

Provide detailed reproduction steps (if any)

1. Go to http://sdk.ckeditor.com/samples/fullpreset.html.
2. Open Source mode and replace content with <input checked required type="checkbox" />.
3. Switch back to WYSIWYG mode.
4. Double click on checkbox to open dialog.

Expected result

Dialog should show that the input is required (required option checked).

Actual result

The required option is not checked.

Other details

• Browser: All
• OS: All
• CKEditor version: 4.7.1
• Installed CKEditor plugins: Full preset

The cause of the issue is described here http://dev.ckeditor.com/ticket/14291#comment:2.