Using !Combat in the skill requirements field works almost perfectly - the icon is greyed out and unable to be used in combat. The problem is it adds the tooltip from the regular combat requirement:
[Linked Image]
The tooltip says it can only be cast in combat, when the opposite is true. Hopefully this is an easy fix, as doing this is preferrable to scripting anti-combat behavior - I'd rather have the icon be greyed out and unclickable.