this is the macro use in raid's that some of the other priest in the guild have
/#showtooltip Shackle Undead
/clearfocus [modifier:shift]
/clearfocus [button:2]
/clearfocus [target=focus,dead]
/clearfocus [target=focus,noexists]
/focus [target=focus,noexists]
/cast [target=focus,harm] Shackle Undead