@JesperWe Thanks for the codepen and description, sounds like the same issue as this one: SlideBox : GetByHandle not working in modal from @WidawskiJ
To narrow down the issue, I think it’s because the abstract tab state has a different historyId as the modal, so when it’s trying to look up the slidebox instance inside of the modal it’s seeing the wrong historyId. I’ll start digging into this to find the fix. Thanks for reporting this!