I have a Surface Pro 4 running windows 10 and followed the soloution this guy found and it worked. Although the app is now tiny I can still pic and grab and copy paste the hex okay. My screen resolution is 2560 c 1600 at 200% scaling. Antoher solution which worked if you can stand it is to keep the scaling at 100% and low the res to around 1600 x 900 or similar.

I just found the solution in this forum by reading the reply of Craig on Sept 4 2015 2:03pm - here it is:

 Magnifier and Cursor do not line up
This happens normally if Windows is scaled, e.g. on a notebook or 4K monitor (125%, 150%...).
I found this solution now, after do so ColorPick has (original) small letters but will hit now the pixel under the mouse:

To fix this problem, right-click the desktop application’s shortcut and select Properties. If the application is on the taskbar, right-click the taskbar icon, right-click the application’s name, and select Properties.

Click the Compatibility tab and click the “Disable display scaling on high DPI settings” checkbox. After you do, close the application and re-open it.
by Craig on Sep 4 2015 2:03pm