* Drag an roster item over a chat view with a lot of text (and thus a 
  movable scrollbar) in it.
* When the mouse pointer, dragging the contact, moves over the scrollbar,
  the scrollbar quickly moves up/down, so that the position needs to be
corrected     
  when the dragging to the notebook is done.

It would be better if the scrollbars of the chat views would ignore the mouse
events while a drag action (of roster items, but maybe also in general) is being
performed.