Seem like you didn't read my post completely...(or didn't understand it)
I said toggle the actual Stopwatch function of the clock and not the visibility of it.
So for instance go to periscope, click on
KEY, observe whatever you want to observe, press
KEY again, and then go to the navigation map, show the Clock/Stopwatch and use the measured Interval for whatever thing you want.
But anyway, thank you for the response.