Update frame positions when model.composition changes,
instead of when model changes. Ensures correct display
after changes to avoid redrawing on every update,
WTD-716.
Add a commit function to scope from the edit representer;
this avoids issues trying to transparently detect and
persist changes made during edit mode, while still requiring
only minimal action from individual views. WTD-535.
Store changes to the size and position of panels in a
layout to its configuration. The mct-representation
directive (and its constituent parts) is responsible
for detecting and persisting these changes as
appropriate. WTD-535.
