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Tar
Aidan

Ah, it’s a bit tricky. The main issue is that you’re comparing a Flex 3 example to a Flex 4 example, and the subtle difference is that the mx:Tree in Flex 4 sets the openDuration style to 0 milliseconds, whereas in Flex 3 the openDuration style was 250 milliseconds. You can add the following code to the application to verify:

<mx:Button id="btn" click="btn.label = tree1.getStyle('openDuration');" />

If you want to add the easing animation back in Flex 4, simply set the openDuration style to 250 milliseconds (or whatever you want) using the following snippet:

<mx:Tree id="tree1"
        openDuration="250"
        labelField="@label"
        showRoot="true">
    <mx:XMLListCollection id="MailBox">
        <fx:XMLList>
            <!-- nodes go here -->
        </fx:XMLList>
    </mx:XMLListCollection>
</mx:Tree>

Or you can change the openDuration for all mx:Tree controls in your Flex 4 application using a Style block, as seen in the following snippet:

<fx:Style>
    @namespace s "library://ns.adobe.com/flex/spark";
    @namespace mx "library://ns.adobe.com/flex/mx";
 
    mx|Tree {
        openDuration: 250;
    }
</fx:Style>

Peter

In the above example, when the label feilds are clicked on there is NO tween/animation to display their children. However in this one…
http://blog.flexexamples.com/2008/04/05/opening-branches-by-clicking-rows-in-a-tree-control-in-flex/#more-588

…They do tween. For the life of me i caunt see where the code is that does that.
Could you point it out for me?
Thanks.