@simosx take any Java app or an app that didn't add workarounds (Gedit was one of the first where it was fixed) and use Ctrl+C on Cyrillic layout (Ukrainian as an example). I wouldn't work even on 17.04. So yes, there are apps (many of them listed in this issue) that kind of fixed it, but the root cause is the GNOME stack and it was not fixed and even not going to be fixed ever (I can't find relevant upstream issue right now, but it was closed as not a bug).
@simosx take any Java app or an app that didn't add workarounds (Gedit was one of the first where it was fixed) and use Ctrl+C on Cyrillic layout (Ukrainian as an example). I wouldn't work even on 17.04. So yes, there are apps (many of them listed in this issue) that kind of fixed it, but the root cause is the GNOME stack and it was not fixed and even not going to be fixed ever (I can't find relevant upstream issue right now, but it was closed as not a bug).