How does 'On-Screen' work?

Hi Guys.

I never really understood the properties of 'On-Screen'.

I want to disable a Tween of an object(s) so it does not run while Not 'On-Screen'. I can't get it to work if there are multiple objects of the same entering the game area. Can anyone clarify what I am doing wrong? Thanks!

You can see the problem in my little test demo here. The Gems are not following the same Tween.

construct.net/en/free-online-games/knight-runner-tester-54377/play

The problem has nothing to do with "is on screen" condition. You should never use "Trigger once" in loops. And never use "Trigger once" with objects that have multiple instances.

Try this code:

Gem is on screen
Gem Tween is NOT running : Gem start tween

Gem is NOT on screen : Gem stop tween