Bug 163345 [Field Assist] - API - Deprecate DecoratedField and related classes
If ControlDecoration is adopted in replacement of DecoratedField by all existing SDK clients, then we should deprecate DecoratedField.
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/DecoratedField.java
if (decDatas[i] != null && decDatas[i].showOnFocus) {
				setVisible(decDatas[i], false);
			}
		}
	}
	/**
	 * Show the specified decoration. This message has no effect if the
	 * decoration is already showing, or was not already added to the field
	 * using <code>addFieldDecoration</code>.
	 * 
	 * @param decoration
	 *            the decoration to be shown.
	 */
	public void showDecoration(FieldDecoration decoration) {
		FieldDecorationData data = getDecorationData(decoration);
		if (data == null) {
			return;
		}
		
		data.visible = true;
		
		
		if (!data.showOnFocus || control.isFocusControl()) {
			setVisible(data, true);
		}
	}
	/**
	 * Hide the specified decoration. This message has no effect if the
	 * decoration is already hidden, or was not already added to the field using
	 * <code>addFieldDecoration</code>.