Adobe Flex: toolTip of a spark component with enabled=false

I have a Spark Component (a Group) which doesn't behave as wanted.

The tooltip is only shown when the component is enabled=true which the following example shows:

<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
               xmlns:s="library://ns.adobe开发者_开发技巧.com/flex/spark" 
               xmlns:mx="library://ns.adobe.com/flex/mx"
               creationComplete="init(event)">
    <s:layout>
        <s:HorizontalLayout />
    </s:layout>

    <s:Group toolTip="test" enabled="false">

    </s:Group>
    <mx:Canvas toolTip="test" enabled="false">

    </mx:Canvas>
</s:Application>

In the Halo component the toolTip is shown. And this is what I want to achieve.

In my case I want to try something like this:

<s:Group toolTip="{cartEntries > 0 ? 'great!' : 'go and buy!'}"></s:Group>

Any hints?

Only workaround: create enabled wrapper container with tooltip.