I posted a question to the forum the other day asking for assistance, and I got an answer which told me to use a Tween behavior. How does one use Tween in their game, because whenever I put it in, the game won’t progress past the first frame (it crashes before it can even start)? I don’t know whether I’m just doing something wrong or what… but I feel like this shouldn’t be this difficult. 
remove the begin of scene
Thanks for the help, but that didn’t work out. It still seems to freeze, and the only time it won’t freeze is when I remove the Tweens!
add Trigger Once when you call the Tween
So I tried it out, and to no avail. I finished the code here, but the crashing still happens. Again, this is a problem whenever I do a Tween in any situation, not even in the context of this project. And it doesn’t look like many other people are experiencing this issue…
TestMove has the Tween Behaviour added?
Well… yeah. I wouldn’t be able to do Tween commands unless I actually added the Tween behavior.
Dumb question TestMove has the Tween behaviour added?
Yes, it does. Not to be rude, but you just asked me that same question a moment ago. I wouldn’t be able to place down Tween code unless I actually added the Tween behavior to TestMove… 
Oh no that is because of the d umb word so the comment must be approbed for mederators sorry
Look this is how i use tweens note the actions are subevents of Trigger Once
In these events i create a 10 cols 4 rows inside of the screen
and outside of the screen are 40 items that tween
I tried out exactly what you said, but still… nothing. Like I said… again, many times before… the crashing is also happening outside of the context of this project. It’s just whenever I use a Tween EVER.
But you still has At Begin of the Scene in a Foreach I think this maybe is causing the issue.
Plus the Condition At Begin of the Scene always runs one time there is no need to call Begin of scene and trigger once in the same event.
I added it back because… again, LIKE I SAID BEFORE… It wasn’t actually the root of the problem.
In all honesty, I really appreciate you helping me out here… but I need something a little more informative.
Sorry for not being able to help you, maybe another user can help you
Alright… So I was testing this situation, and I figured out that it crashes due to a combination of things: The fact that there is a “Repeat for each instance of TestMove”, and also the fact that… even without it, the Tween just never happens. And the condition is stuck in purgatory to never finish. This is all very confusing… jeez.
Can you reproduce the problem in a small project and share it so people can try for them self and see if they can find a work around?
When something does not work, often it is caused by the code generate by GDevelop and not always obvious what is happening by only looking at the events. Sharing only screenshots and expect someone to solve the problem for you is not always as straight forward as you might think. The only thing we can do is “try” things and see if it makes a difference 
i am fairly sure, your problem is your event structure, not with tweens in itself.
i assume you are stuck in a loop that cant be completed, thats why your game doesnt start.
a repeat for each at the beginning of the scene should look like this:
to make things clear:
do you still move your testmove objects just up and down?
if so you overcomplicate it.
it would be easiest to help you, if you upload your project and explain exactly whats supposed to happen.
You have a for each testmove inside another for each testmove. So if you have 10 objects, you’re starting 10 times the same tween on each instance. Don’t do that.
