We refactor a current COM registered tool to an Add-in.
The tool drawing a circle on the screen and some measuring on a screen map.
It appears INewCircleFeedback : IDisplayFeedback to have in DMS(Degrees Minutes Seconds) instead of metres.
We changed on a Data Frame Properties - Units - Display: to Metres. It did not helped.
We cannot change Data Frame Properties - Units - Map: (it appears Decimal Degrees)
The value of the measurement is 0.00015898806739755855 instead of 10 or 20 meters.
to make things worse, at the time of a measurement the Distance Units appears to be in metres:
ArcMap 10.6.1, VS 2017.