I use 3 layouts: Russian, English and Italian. I need all them in LFS as well. Before all three worked fine, but in Y Italian doesn't work correctly for me. Instead of symbols like è à ò ù ì, I get those without diacritic signs: e a o u i. Windows XP64. Before patch Y it always worked.

Hmm, by "layout" do you mean something to do with the keyboard? Not an autocross layout I suppose!

I was confused at first because I've just been loading languages to see the bug and I do see some accents on letters in Italian (not many) and in French (several) so I assume this is not a problem with text drawing.

So I guess the problem is only a typing problem. In which case I cannot see how LFS could be the cause. I haven't changed anything in the keyboard input systems. I can (also in Latin-1) type ALT+(numpad)130 and I get an e-acute (é) in LFS just like I do here. Could it be something has changed on your computer and in fact this would also affect a copy of version X as well?