Auto detection of the languages

Page is supposed to detect automatically the language that is typed in a document. But it doesn't work. I went to "settings" and in "Text and Language" to specify the languages that I use and the order in which the application should attempt to recognize. If my list contains English and French, in that order, the application should assume that the text is english; but after too much spelling errors, it will try to work in French (as it works in MS Word). However, the auto detect does not do that.

I can force it manually in Inspector but it should work automatically. Any ideas?