Despite the fact that you can have the appearance of the document being blurred and having no active selections, we will always keep the last valid range as the current selection. This is a case of the model not matching the view.
The other solution (as used by Google Docs) is to always render a selection even when the document is unfocused, but as we are using native selections this may not be possible.
Version: unspecified
Severity: enhancement
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=62410