I'm using the latest EZ-Builder for Windows (2017.01.08.00) with a fresh copy of the JD Example Project.
When I enable Red color tracking I get the expected head and arm movements with JD following my MOVING red object.,, very nice!
However, when I hold the red object STATIONARY, I found that JD's head continuously scans back and forth as if it can't lock unto it
I then enabled the "Use Grid Lines" checkbox and JD zeros in perfectly!
From the "?" icon I can see that without grid lines JD will use the center of the image, but in my testing he never settles on it
I there a downside to enabling Use Grid lines?
BTW, in looking through the learn- Activities- Color Tracking with Movement course I see the Note: that this tutorial not for JD and that its covered in another tutorial, but there is no link and I can't find it.
Also, there is no "Use Grid Lines" checkbox in the Step 2 Settings snapshot although it is available in the Camera Config screen in EZ-Builder
There's no advantage to either. It's the two ways a robot can track/center objects. It's great that you have experienced both.