Called by the snip to request scrolling so that the given region is visible. The snip generally needs to be updated after a scroll, but the snip decides whether the update should occur immediately.
The result is #t if the editor is scrolled, #f oitherwise.
The method call is ignored (and the result is #f) if the given snip is not managed by this administrator.
The localx, localy, w, and h arguments specify a region of the snip to be made visible by the scroll (in snip coordinates).
If refresh? is not #f, then the editor is requesting to be updated immediately.
The bias argument is one of: