A customer pointed out to us that in some cases when a Tree’s scrollPolicy is set to ‘auto’, the scrollbar doesn’t show up when you add data and it doesn’t disappear when you remove data. This bug only shows up in Flex 2.0.1 with our latest released hotFix. The bug is not in Flex 2.0.1 and it is NOT in the Moxie Public Beta. The example below is the original Application which has a delay (created by a Timer) before adding a bunch of nodes to the Tree. When the nodes are added and a scrollbar is needed, it does not show up.

Original Bug Application : treeScrollAuto.mxml, treeScrollAuto.swf

After spending some time looking at this Deepa Subramaniam came up with the following solution to this problem using a custom dataDescriptor.

Fixed Application : treeScrollAutoFixed.mxml, myDescriptor.as, treeScrollAutoFixed.swf