SHORTCUT for 'lock screen' is NON_FUNCTIONAL with <Mod5> key

[이상현 <hiuni3 snu ac kr>]

In FC6, using Gnome, 
If I set the keyboard shortcut for 'lock screen' to any combination with
<Mod5>, ex) <Mod5>l, it doesn't work. 
The <Mod5> key is 'windows' key, by checking 'Press any of Win-keys to
choose 3rd level' in 'Keyboard Preferences'.
'lock screen' shortcut work well with any combination with
shift,ctrl,alt.
Some shortcut's are working well with <Mod5> combination. For example, I
use <Mod5>t for 'Run a terminal' and something more. 
What's the problem??

-- 
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ㅣ 이상현; leE, Sang Hyun