I also tried on runtime, and it does the same things.
I also tried the uniform grid panel, and it seemed even more confusing than the standart grid panel…
thanks for your suggestion, it’s kind of hacky but well I can’t find another solution
If somebody has a cleaner solution, I would be glad to hear it. The more I dig into unreal UI, the more I feel like it just does not work, like if it was still in beta or something