Yosemite changes QWERTY keyboard layout

keyboard

I have a qwerty keyboard, but I type in french and japanese quite often.

Up until now, I used to have kotoeri activated with Romaji writing for english and french. I used to write accentuated letters by :

option + e + letter for é, ó, etc…
option + ` + letter for à è ù etc…
option + i + letter for î, û, ê, etc…
option + u + letter for ü, ï, ö, etc…

Under yosemite, this doesn't work anymore.

To get it back I had to activate US International – PC. But it still doesn't work properly. There is a huge bug :

when typing ' then a letter, I get á, é, etc… This is preventing me for writing properly stuffs like

l'arrosoir → lárrosoir
qu'un → quún

There are a lot of stuffs like this in french. And even worse, auto-correction kicks in and transforms:

quún in quant

How can I fix this ? How can I still continue typing without learning a new keyboard layout ?

CLARIFICATION
=============

I am talking about several separate bugs.

Bug on U.S. International PC keyboard layout

While using this keyboard pressing option + e then a vowel produces the right output (for instance á) the key 'actually adds an accent to a letter instead of producing the 'character (for instance quelquúninstead of quelqu'un). This is most inconvenient as the character ' alone is quite frequent in french.

Bug on U.S. keyboard layout

Hitting option + e then a vowel has no effect (same for option + u then a vowel, etc…)
→ Solved by deactivating and and activating again this configuration. This is the only working configuration.

Bug on kotoeri

Kotoeri configuration let the user choose which keyboard configuration to use for romaji. I have selected U.S. as usual, and I have the same issues as with the U.S. configuration below. If I select US International PC, nothing changes, I don't even get the behavior of International PC without kotoeri. This is most definitely wrong.

UPDATE
======

Selecting US Extended yields the desired behavior (the old one from US international PC). However, US Extended is not available for kotoeri.

Best Answer

I'm also a kotoeri user, and it took me a while to understand what's wrong.
In fact, the former behavior (e.g. option-e, then e = é) is not available anymore
in kotoeri alphabetic (symbol A in the task bar). However, it's still available in the
US input (symbol american flag in the task bar).

What I wanted to do:
- Switch between european languages and japanese with command space;
- Get the former behaviour when in european mode.
What I did:
- Open the preferences, go to input sources;
- Remove everything except U.S and Japanese hiragana;
Then it works again. The only difference is that it used to be either
alphabet (letter A) and now it's the US input (American flag). And in
american mode, you can use all the former option + key combinations.

That's it!

Pascal