- the propaccumulator needs a method of compensating for additions in the content accumulator. or this could be done via the blockeditor.

- need a method of linking inserts between accumulator and propaccumulator. This could be done via a callback in the accumulator or somehow at the blockeditor.

- vif should employ 'dirtybits' and only redraw those during Redraw

- the display filter displays rows, the start and end of these rows are dictated by the navigator, which determines them based on the view mode (text, binary, etc) The displayfilter determines the number of the rows that are displayed (via start and end), and uses a bookmark to forward this information to the rest of the system.