I'm a beginner at this, with SW 2014. I have tried relentlessly to produce this tool. Besides the book stating, Where to find it: "Right-click the top-level part icon and click Show DRV", and to use it, "Toggle DRV on and float over the -- feature"  The part icon is the block-like upside down T shape; the very top line of the Feature Tree, if I'm not mistaken. I have right-clicked on this, and on my top level feature, but don't see the DRV icon, shown in the book. When I right-click on the top feature, I do get the selection list having the Parent-Child relations button. Nothing happens when I hover over the features in the tree.