The width:height ratio of a typical sequence diagram is too large when exported
to graphics files for inclusion in user manuals.

The vertical spacing of methods is currently satisfactory. On the other hand,
the horizontal spacing of lifelines is too great. The horizontal spacing is
determined by the combined width of the object:Class labels at the top of the
lifeline.

In other UML editors, I have seen two ways of reducing the width. I would like
to see any one of these (or both!) implemented:

1) Allow the object:Class labels to be on two lines. For example:

object:
Class

2) Allow the vertical position of the label to be draggable, without altering
the horizontal position of any attached messages. This allows labels to be
placed along two rows at the top of the page, rather than in a single row. The
resultant configuration looks like two rows of bricks. The second label would be
dragged above and partially overlapping the first label. The third label would
be partially below the second label. And so on. 

Ideally, this second method would have a user-defined option. The labels could
either be in one row (the current setting) or in two rows of bricks.  When the
diagram is produced automatically by reverse engineering, the appropriate option
would be invoked.