This controller is called Manipulator
. There were several bugs related to that in V10.X, which seem to be fixed, to much...
Take a look here and on linked topics:
Manipulator reset bug
Let's take an example from this thread, the issue described here is fixed in 10.4.X yet yours isn't:
x = 0;
Manipulator[Dynamic[x, (Print[#]; x = #) &], {-10, 0}]
Proceed with: Evaluate -> Open Manipulator -> enter 3
-> Click somewhere outside.
x == -7
now...
I'd report that.