Panel slide problem - need help

This is very helpful, thank you. Altho i have one more question. How can i track one panel position inside of scrolling panel (horizontal)? I try with Window.ScrollX but would not work. I want to track every panel so i can than do IF statement for positioning.
Another question, i want to do something like: IF scrollX is 24 than fix panel at 24, is this possible? When panel scrolls to some scrollX value, it gets fixed and does not scroll?
Explanation is here: https://imgur.com/a/RVGAG
Or you could answer in my other topic: Dynamic horizontal stacking panels with scroll

Scrolling panel.rp (55.7 KB)

Sorry for all these questions, i really hit the wall here.