I cannot duplicate your problem. I am using DPP version 3.7.2.0 and it works fine. I click on the dropper and then click on the white I want to use as my reference. The image adjusts and then I hit register and pick 1, 2 or 3 and click on OK and it is registered. I just tried it a couple of times and it worked fine. I just installed and have updated DPP, but I let it choose default settings.


Possibly your security is not allowing you to do it. You may need to change permissions for DPP. I use Kaspersky and I added DPP as "trusted" when I set it up. This is the first thing I can think of, I hope it helps you.


Chris