Widget ScrollBox doesn't work in a vertical orientation?

Hi, I made an editor utility widget and after adding more features to the widget it became too big to fit in its corner on the screen. To let me access the now hidden features I added a ScrollBox.
The ScrollBox worked perfectly in a horizontal alignment, when the widget window became too narrow a scrollbar would appear and let me scroll to the hidden features. However, when I tried to do the same for the widget being too short by adding another scrollbar and setting it to a vertical alignment the scrollbar did not appear.
Has anyone encountered this before? The only thing I have changed compared to the working scrollbar is the alignment. I may be missing something obvious but I just can’t get the vertical scrollbar to appear. Thanks in advance for your help!