This is less a question than a notification of something I discovered.
I adopted the code from the DisplayAdjust Demo to limit brightness and contrast adjustments to the area selected: To wit,
ImageEnView1.IEBitmap.AdjustmentsMask.Assign( ImageEnView1.SelectionMask );
if ImageEnView1.IEBitmap.AdjustmentsMask.IsEmpty then
This was not working with my application. Any Contrast or Brightness change was applied to the entire image whether or not there was an active selection. It turns out that the following line in my startup code was causing this result.
Pic.ZoomFilter := rfLanczos3;
It appears that Setting a ZoomFilter other than rfNone has the above effect.