Colour customisation is extremely limited in X2 and half of what's listed in the colour page simply do.not.work.
This has been an ongoing source of frustration for a lot of users since X1 was introduced. Up until then, all of the options on the Colours dialog worked, but even this implementation was only half baked
For your situation, if you have the Inspector open (press 'i') and at the top you'll see separate tabs for Track & Clip - click one of these and try your colours there. Most of these do actualy work.