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
label.setBackground(form.getBackground());
			label.addMouseTrackListener(new MouseTrackListener() {
				public void mouseHover(MouseEvent event) {
					FieldDecorationData decData = (FieldDecorationData) event.widget
							.getData();
					String desc = decData.decoration.getDescription();
					if (desc != null) {
						showHoverText(desc, label);
					}
				}
				public void mouseEnter(MouseEvent event) {
				}
				public void mouseExit(MouseEvent event) {
					hideHover();
				}
			});
			decDatas[i] = new FieldDecorationData(decoration, label, formData,
					showOnFocus);
			
			
			updateControlAttachments(i, decDatas[i]);
		} else {
			label = decDatas[i].label;
			formData = decDatas[i].data;
			decDatas[i].decoration = decoration;
			decDatas[i].showOnFocus = showOnFocus;
		}
		label.setImage(decDatas[i].decoration.getImage());
		label.setData(decDatas[i]);
		label.setVisible(!showOnFocus);