- If you move the horizontal scrollbar far to the right so that the code is no longer visible (add lots of spaces if you have to), then try to navigate to the test, does the horizontal scrollbar move in any way?
When I've tried to do this, I had to turn of WordWrap (Ctrl+E,W) - I don't know why I had this on. But after turning this off, scrolling started to work as expected.
I've submitted bug report