hello @RafaŁ-Buchner, yes, I think it’s a good idea to remove the observer in your code. here’s what the defcon documentation says: Don’t Forget removeObserver The only real gotcha in this is that you must remove the observer from the observed object when the observation is no longer needed. If you don’t do this and the observed object is changed, it will try to post a notification to the object you have discarded. That could lead to trouble. and here’s an example script in which the defcon Glyph.Changed observer is removed when the current glyph changes.