UIScrollView scrollbar disappearing when using setScrollIndicatorInsets:

Question

I am trying to reposition my scrollbar in a subclass of UIScrollView. According to the API docs this should be as simple as:

 [gridView setScrollIndicatorInsets:UIEdgeInsetsMake(0,0,0,10)];

However when I pass anything to this setter that is not UIEdgeInsetsZero, the scrollbar completely disappears.

The scrollbar I am trying to move is a right-hand-side vertical bar, and I have tried a range of values from negatives to floating points < 1 and nothing works.

The weird thing is, even when I pass in (0,0,1,0) where the '1' represents what should be the BOTTOM inset, it still makes the bar disappear.

Does anybody have any idea what is going on? It seems like I am missing something obvious...