double minX = totalBounds.getMinX();
double minY = totalBounds.getMinY();
double maxX = totalBounds.getMaxX();
double maxY = totalBounds.getMaxY();
Color c = model.getForeColor();
diagram.add(new RectangleElement(
minX - d, maxY + d, maxX + d, minY - d, c));
diagram.add(new TextElement(
(minX+maxX)/2, minY-d, "Reactants", c));
return diagram;
}