Photoshop :: Healing Brush CS2

When editing with the heal tool in Photoshop CS1, I found that I could use a selection to limit what was sampled and modified by the heal tool, but not in CS2.

For example: In CS1, If i needed to 'heal' an area of a photo that contrasted with an adjacent area (that would influence the heal tool), I would make a selection of the area I wanted to heal, which would render all areas outside the selection unusable by the heal tool, so that only the area inside my selection could be sampled / modified by the heal tool. Here is this 'trick', explained in Photoshop Help:

"If there is a strong contrast at the edges of the area you want to heal, make a selection before you use the Healing Brush tool. The selection should be bigger than the area you want to heal but should precisely follow the boundary of contrasting pixels. When you paint with the Healing Brush tool, the selection prevents colors from bleeding in from the outside."

Working with CS2, I find that this little trick does not apply. Whether or not I'm working within or outside of a selection, or not working with one altogether, makes no difference to which pixels the CS2 heal tool uses - it uses all available pixels, and is not confined by a selection as it was in CS1. With CS2, I find it impossible to use the heal tool in areas of high contrast, where I could've (with the use of a selection) in CS1. Am I unique in this? Is this a glitch with my version of CS2, or a glitch with CS2 altogether?

How id it corrected, so that a selection can be made to limit the pixels available to the heal tool?