i don't know where is the problem.I'm thinking that is a bug, because if i use the matrixctrl it works. if you can see the png it has the not clicked image (yellow knob) and the clicked image (blue knob). But it doesn't work.
So you’re trying to make it yellow until the user clicks/drags it, at which point it will turn bluish-green? Sorry I don’t have much experience with [pictctrl], but try sending the "clickedImage 0" and "clickedImage 1" messages. If that works, perhaps you could hack it into whatever you want.