(perhaps this one can be considered as a bug?)
The AutomaticCanvasSize property doesn’t expand to completely fit the size of the newly added UI.
This is the last frame added to this ScrollingFrame, you can see it’s scrolled all the way down, but doesn’t cover the entire frame. I don’t think there are tricks around this, and if there they are probably really frustrating.
If the AutomaticCanvasSize accounted for this, life would be easier!
Update: the problem seems to only occur if the position was using Scale? and also depends on the AnchorPoint