This version?

And I think, you need to start learning something new, something useful and indeed extremly powerful... Arrays! They will improve undo/redo system so much. Just sit down and start learning. I mean really, nowdays there thousand of books/videos/tutorials on the internet, arrays is not something that is very complicated (although it might look like that at the start) compared to some other "programming stuff".

I wonder, are you using "No save" behavior?

It hard to say whats wrong without an example project, but in case you still didn't solve a problem I suggest you to start from scratch (I mean not from a complete scratch of course). Backup your original project first, just_in_case, then delete all save/load events, buttons and probably undo/redo related events.

Start from buttons (do not implement button hover animation, forget about it for a while) events, then save/load system and at the end undo/redo. Then try to use normal events like "On click"/"On object clicked" (instead of mouse release and overlap/hover combo), remove all "wait for previous" actions and replace them with triggers (for example, when Ajax requests file, create Ajax "on complete" trigger event and etc). Next thing I personally don't like (and never ever use events like that) is that you have trigger events inside continuous events (like you did in "OBJECT CONTROL" group with "on scroll" inside hover event), let triggers be always on top of continuous events. And make sure that every new set of events works as expected before moving to the next one, its easier to catch one bug in one place, instead of thousands of hundreds in multiple at the same time.

When I click your link I'm getting "access denied" error.

Fixed

Try adding "System For each Sprite" to the On timer event.

Its "trigger" event, it cant be inside loop, only on top, but it makes no sense...

Well, it worked, but i wonder why it doesnt without loop?

Faced with some strange behavior of the timer.

I need to make a delayed animation with the wave effect ... i.e. when you click on any sprite, other sprites to the left and to the right of it will start a timer with time as on a screen.

The array contains the UIDs of the sprites, ax variable of the sprite store the index in the array.

When I click on sprite, I loop through all the sprites, first to the left and start the timer with a time that increases with each iteration of the loop, same to the right.

The trick is that if you click, for example, on the 4th sprite, then the first 3 sprites on the left will react to it as expected, BUT the first 3 sprites on the right are not. The rest will also react normally.

Now the fun part. If to do so:

visually, everything works, but the data in the array is not updated...

Am I doing something wrong or what?

Demo project

P.S. same behavior in C2 :/