anyone use vuhdo that can help me?

I installed vuhdo and tried to configure it for my priest.
left click = flash heal
right click = greater heal
center click = renew
4th button = power word:shield

everything works fine... out of combat that is.
once my priest has entered combat, left & right click don't seem to do anything.
I can only renew and shield.

my team doesn't need much healing so it took me while to figure out it wasn't working.
nothing worse than needing a big heal and nothing happens.