I don't see the difference between those two points... I will need to have several tabs that each scroll on their own, but once that is established, all of them can receive more items to display. The entire QTabWidget, however, will not need to be viewed through a scrolling area.

I must say, the interactions between layouts, parent pointers, basic widgets and "container" widgets can get pretty complicated. Very many possible permutations in this case, for example: when to set parent to "this" and when not, what gets added to what and in which order.