Weird, I do get scrollbars with that code. Could you show a complete code, something that I can copy, paste and run so that I have the exact same code?
But the clipping is definately broken, seems like it only took 4 days for someone to find a bug in the new implementation.
The scrolling also seems a bit wrong, I either terribly messed something up in the new clipping code (which was just rewritten from scratch to work around and SFML issue) or there is some other issue in ScrollablePanel that I never noticed yet.
The widgets you are playing with are all relatively new or received quite some recent changes and are thus less tested, so you might hit a bit more issues with them than usual.
Writing something like that is probably not going to be easy, but maybe you can try with a VerticalLayout instead of a Grid. It requires you to manually specify the size, but you might be able to easily calculate it. The width would just be the size of the ScrollbablePanel (maybe minus the scrollbar width) while the height is the amount of items multiplied with the height of each row. You would have to change the height of the VerticalLayout every time you add or remove a row, but I think it might be the best solution.