Trying to edit a missing object property with the new WYSIWYG editor can lead to infinite include recursion

Follow this steps to reproduce:

• create a XWiki class, like XWiki.MyClass, and add some properties. Include one property (lets call it A) that is editable with the WYSIWYG editor
• create a sheet for XWiki.MyClass, like XWiki.MyClassSheet
• create a page Space.MyPage and add an object of type XWiki.MyClass
• set the content of Space.MyPage to:

  {{include document="XWiki.MyClassSheet"/}}
  

• Edit XWiki.MyClass and add a new property that is editable with the WYSIWYG editor (let call it B)
• Edit Space.MyPage in inline mode

The editor for the first property (A) has the right content (empty string or the value of the property) while the editor for the second property (B) has the content of Space.MyPage, which is the include statement. If you try to save you'll get a infinite include recursion (the sheet displays the property which includes the sheet which displays the property which ...).