Graphic2D window does not update on object deletion

[typically]

When an 3D shape object is deleted (via tree panel), 2D windows still show the object. This appears to be because they are not being regenerated.

Reproduce:

Load object into memory, view on Graphic2D window, delete via tree panel.

[typically]

Possible fix: Check/modify the path ShapeSet3D ShapeRemoved event to Graphics2D window via listener interface.