Yes the srollerShutter was a typo which happened when I updated the post after your first hint.
What did the trick was the true in the end.
While trying to find the “last line of the lambda” I stumbled across your tutorial ""reusable functions, a simple lambda example
which cleared things up a lot for me. I even got ride of the warning that i should use parameterized functions ^^
Out of curiosity one thing remains that I don’t quite understand, is there a difference between
createTimer (now.plusSeconds(runtime)) [ |
//Timer code goes here
]
and
createTimer(now.plusSeconds(runtime), [ |
//Timer code goes here
])
Besides that a big thank you for your help 
, seems like there is still a lot to learn for me.
Without you I wouldn’t have found a solution anytime soon.
Wish you a nice day and thanks again!
Anton