Dear maintainer,

All Korean 101/104 keyboard(adopted at most of Korean laptops) users encounter the same issue whenever they install new linux dist like shown below. 

https://bugs.launchpad.net/unity/+bug/940927
http://katselphrime.wo.tc/2012/09/15/how-to-fix-right-alt-hangul-key-issue-in-unity/ (sorry, written in Korean, but you may refer some images here...)
http://ubuntu.or.kr/viewtopic.php?f=20&t=23583 (written in Korean)

The issue is that Korean 101/104 keyboard utilizes "Right Alt key" for just "Hangul key" exclusively without any modifier function, but the current Korean 101/104 keyboard's symbol configuraion fires "Hangul key with Mod1 modifier". (Also Hangul_Hanja key is the same.)

Because of this issue, some users fix this issue with changing ubuntu hud shortcut key from Alt key to another key, and other users fix this issue with executing "xmodmap -e 'remove mod1=Hangul'" command at the booting process.

Yes, I agree with that ubuntu might have a problem too. But IMO, in order to support Korean 101/104 keyboard properly, Korean symbol configuraion should be like shown below. 

partial hidden function_keys
xkb_symbols "koreankeys_raltctl" {
    key <RALT> {
      type[Group1]="ONE_LEVEL",
      symbols[Group1] = [ Hangul ]
    };
    //key <RALT> { [ Hangul ] };
    key <RCTL> {
      type[Group1]="ONE_LEVEL",
      symbols[Group1] = [ Hangul_Hanja ]
    };
    //key <RCTL> { [ Hangul_Hanja ] };
};

Or redefine Mod1, Control as modifier_map Mod1 { Alt_L, Meta_L };, modifier_map Control{ Control_L};...

But no matter how you fix this, I would be appreciated:-)

Thank you.