This might be a newly introduced bug. I
seem to recall there was no vertical scroll bar when paged view was
first introduced.
There now is a scroll bar in paged/column view, and the thumb position is random/incorrect. Dragging it
anywhere just deposits you at the beginning of the resource, so it isn't
very helpful.
EDIT: I can't reproduce the behavior of dragging dropping you back at the top. But if you page all the way down in the resource using the Page Down key, the thumb doesn't move from the top. Then if you grab the thumb again, it does pop you (temporarily) back to the top of the document since that's where the thumb is at the moment. This might have been what I was seeing. But I could have sworn that no matter where I dragged the thumb, it left me at the top.
