setxkbmap dosn't work (with KDE)

[Yuri]

I am trying to enable some key combination to switch
between keyboard layouts.

Command 'setxkbmap -option grp:alts_toggle' is supposed to
enable layout switching by both alts. But alts don't do
anything after it. Same with 'setxkbmap -option grp:caps_toggle'.

setxkbmap is from setxkbmap-1.0.4.

This must be a bug somewhere.
Anyone also experiences this problem?

Yuri