Bug 129214 [Field Assist] - Decorated Field attachments not centering images horizontally
DecoratedField is supposed to center decorations horizontally on each side. The current attachments are not doing so. Also consider whether grid would have been a better choice for internal implementation.
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/DecoratedField.java
data.left = new FormAttachment(0, 0);
			data.bottom = new FormAttachment(100, 0);
			break;
		case RIGHT_TOP:
			data.right = new FormAttachment(100, 0);
			data.top = new FormAttachment(0, 0);
			break;
		case RIGHT_BOTTOM:
			data.right = new FormAttachment(100, 0);
			data.bottom = new FormAttachment(100, 0);
			break;
		}
		data.width = widthOf(image);
		data.height = SWT.DEFAULT;
		return data;
	}
	/**
	 * Show the specified text using the same hover dialog as is used to show
	 * decorator descriptions. Normally, a decoration's description text will be
	 * shown in an info hover over the field's control whenever the mouse hovers
	 * over the decoration. This method can be used to show a decoration's
	 * description text at other times (such as when the control receives
	 * focus), or to show other text associated with the field.
	 * 
	 * <p>
	 * If there is currently a hover visible, the hover's text will be replaced
	 * with the specified text.
	 * 
	 * @param text
	 *            the text to be shown in the info hover, or <code>null</code>