When manually re-ordering tasks in the Windows client, if I am trying to move a task beyond the area that is visible on the window at that time, the list does not scroll to allow me to do this. What theat means is that if I have long list of tasks, that is going beyond my visible area, I have to move the task down as far as I can, scroll the list down, move the task down again etc.
I consider this a bug, you may consider it a feature request :-)