A sequence with more rows than fit on screen would not scroll to the last ones -- scrolling only packed the visible rows tighter, and dragging the window bigger was the only way to reach them. Loop and If rows render a little taller than plain step rows, and the list sized its scroll range as if every row were the shorter height, so the range fell short of the real content. The list now measures each row at its true height, so long lists scroll all the way to the final step.
When you dragged a step to a new position, the drop target was figured from a single fixed row height, so in a list with taller Loop or If rows the step could land a slot away from where the indicator pointed. Reordering now goes by each row's real on-screen position, so the step lands at the drop line -- including when you drop a row inside an If branch.