limey

I've been trying to do what I saw done in one of the tutorials on the CD that came with CS2.
In the tutorial the instructor makes an artist who is painting in a field of flowers with a blue sky disappear from a picture by using the Spot Healing tool. The artist is half in the field and half in the blue sky so I thought it was a pretty cool feat that the tool was able to accomplish this.

I picked what I thought would be easy exercise for the spot healing tool by choosing to remove a picture on a solid coloured wall.
I've had some measure of success trying to perform the exercise but I always get part of an object that is a fair distance away appearing in the place of the object I'm trying to get rid of.
I've tried changing the size, diameter and spacing of the brush but it doesn't make any difference. I also have chosen the Normal mode and the Proximity Match type.

Is there something I'm missing here.