Bug 126527 [Field Assist] - API - Field Decoration alignment issues are different for cell editors
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/DecoratedField.java
public void paintControl(PaintEvent pe) {
					pe.gc.drawString(text, hm, hm);
					if (!CARBON)
						pe.gc.drawPolygon(getPolygon(true));
				}
			});
			hoverShell.addMouseListener(new MouseAdapter() {
				public void mouseDown(MouseEvent e) {
					hideHover();
				}
			});
		}
		/*
		 * Compute a polygon that represents a hover with an arrow pointer. If
		 * border is true, compute the polygon inset by 1-pixel border. Consult
		 * the arrowOnLeft flag to determine which side the arrow is on.
		 */
		int[] getPolygon(boolean border) {
			Point e = getExtent();
			int b = border ? 1 : 0;
			if (arrowOnLeft)
				return new int[] { 0, 0, e.x - b, 0, e.x - b, e.y - b,
						hao + haw, e.y - b, hao + haw / 2, e.y + hah - b, hao,
						e.y - b, 0, e.y - b, 0, 0 };
			return new int[] { 0, 0, e.x - b, 0, e.x - b, e.y - b,
					e.x - hao - b, e.y - b, e.x - hao - haw / 2, e.y + hah - b,
					e.x - hao - haw, e.y - b, 0, e.y - b, 0, 0 };
		}
		/*
		 * Dispose the hover, it is no longer needed. Dispose any resources