Facilities.
The editor shall provide a grid facility where a matrix
of horizontal and vertical lines provide a background
to the editor window. This grid shall be a passive grid
where the alignment of entities is the user's responsibility.
Rationale: A grid helps the user to create a tidy diagram
with well-spaced entities. Although an active grid, where
entities 'snap-to' grid lines can be useful, the positioning is
imprecise. The user is the best person to decide where
entities should be positioned.
Specification: ECLIPSE/WS/Tools/DE/FS Section 5.6