Chroma key problem

Question

can I completely customise a colour selection? I have a shot with a lot of blue in it, deliberately, and a small area of green, basically a mini-green screen, that I want to key out. whenever I add the chroma key filter to it it seems to automatically remove the blue. I've tried using refine key>sample colour to choose the green, which works, but only adds the green to the blue. using the colour selection produces the same effect, I can't move the blue line beyond the blue section.
what I'm assuming is happening is that FCPX is automatically detecting the blus in the shot and "deciding" for me that this is the colour to remove, which it isn't. I can't find a way to use chroma keyer without this incredibly annoying automatic feature turned on. I've tried to 'reset parameters' in the chroma key inspector which just removes any adjustments I've made.
I'm new to FCPX having had to move from FCP7 because all our college computers got upgraded. I'm used to being able to use the old key effects where you could select very specific colours and have complete control over range, spill, etc. so this new lack of control is incredibly frustrating.
thanks

Answer 1

I've tried reseting every one of the seperate selections and nothing happened. playing around with it more I've found that dropping the strength to 0%, effectively removing the key and then using the refine key to select the green works, which seems weird to me. I can't adjust the strength beyond 0% though as that still effects the blue in the shot.
it's the automatic nature of the keyer that is bothering me, it seems to select the colour from the shot before I've done anything. in a previous green screen shot, where it was a more standard setup it automatically selected all the green in the scene. the control with the sliders, refine key, etc. are great, I just wish there was a way to turn off this initial auto-select.