Bug 126233 [FieldAssist] DecoratedField should not automatically reserve space on field ends
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/DecoratedField.java
if (decDatas[i] == null) {
			formData = createFormDataForIndex(i);
			label = new Label(form, SWT.HORIZONTAL | SWT.VERTICAL | SWT.CENTER);
			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);
		} else {
			label = decDatas[i].label;
			formData = decDatas[i].data;
			decDatas[i].decoration = decoration;
			decDatas[i].showOnFocus = showOnFocus;
		}
		/*
		 * Layout data reserved width and height depend on whether
		 * there is an image or this is a blank decoration.  Always
		 * set both values since we may be reusing a form data.