I have been using Linux on and off for 10 years, and more recently I have spent more time with OSX.

But, I still remember that in the beginning I'd choose the US international keyboard layout and it would have exactly the same output as the Windows keyboard layout (and most recently, the OSX US international layout).

However, a few years ago when I installed Ubuntu, I noticed that the cedilla wasn't printed anymore (ç or Ç). This is a combination of the following keys: ' + c. Instead, what I get is the c letter.

When did it start to happen, and why the difference to the behavior on the other OSes? What puzzles me even more is that there is even an "US International alternative" keyboard layout, which prints exactly the same keys! So, what's it alternative to?

This has been reported as a bug back to Canonical (can't find the link now), but the keyboard layout has never changed back to what I'd expect. I know the workarounds to fix it to what I need, but I just would like to know why/when it has become different.