This page is about the magic wand.
Set masking first. Make sure ALL SLICE is not selected (prevent select EVERYTHING. Go through individual slice and click away.
Note: except in version 5.0 and 5.2, you can find Improved Magic Wand tool in the Segmentation Editor - The data range of the Magic Wand tool can be adjusted interactively without resetting the seed point. The seed point's data value is indicated in the data range slider. (http://www.amiravis.com/release521.html)