xmodmap: how to map Alt_L+w to arrowUp

I've been play开发者_如何学Going with this for hours and I can't figure it out.

I would like to map the WASD to the arrows but only when pressing ALT_L + (wasd).

I used xmodmap

Here is what I have so far.

keycode 25 = w W KP_Up ! also tried Up....
clear mod1 
add mod1 = Alt_L Meta_L

The only time I managed to make it work is with the Shift_L e.g keycode 25 = w Up works fine but I lose "W"

Also tried using the Super_L in mod3 (and failed) ... but I really want the Alt_L.

Finally, the Up seems to overwrite the w key in some cases. If I use something else (e.g less), it works.

Please advise.

Thanks,

-hbt

PS: Perhaps you could clarify modifiers for me? I don't seem to get it

Nevermind. It was an issue with chrome

http://code.google.com/p/chromium/issues/detail?id=32304

Upgraded gtk and my mapping works now.