* When undoing, inheritance view is selected and an arrow points to a
  entity view of which the attributes/relationships are reduced, then
  the underlying model view isn't repainted correctly.

* When opening a file, the NSBrowser should reveal as much columns as possible

* Does not open NIB based Editors

* some drawing glitches
  - the separator between the entity name (EntityMiddle?) and the attributes is missing
  - white box at the right side of the drawing area toolbar

* not compatible to .xcdatamodel and .mom