Left click on the secondary skill icon to get the skill menu, then left click on another skill or the special move icon (you can also hover the mouse cursor over an icon and press a function key to set a hotkey, to quickly switch back to frequently used secondary skills).
Lockpick is another annoying skill to accidentally try in the middle of a group of orcs.
Possibly of interest:
Tutorial-Changing F1-F12 hotkeys to different keys.
