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
*            the decoration relative to the field, and the constants
	 *            <code>SWT.TOP</code> and <code>SWT.BOTTOM</code> describe
	 *            the vertical alignment of the decoration relative to the
	 *            field. Decorations always appear on either horizontal side of
	 *            the field, never above or below it. For example, a decoration
	 *            appearing on the left side of the field, at the top, is
	 *            specified as SWT.LEFT | SWT.TOP. If an image decoration
	 *            already exists in the specified position, it will be replaced
	 *            by the one specified.
	 * @param showOnFocus
	 *            <code>true</code> if the decoration should only be shown
	 *            when the associated control has focus, <code>false</code> if
	 *            it should always be shown.
	 * 
	 */
	public void addFieldDecoration(FieldDecoration decoration, int position,
			boolean showOnFocus) {
		final Label label;
		FormData formData;
		int i = indexForPosition(position);
		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);