I assume you are referring to the tree control custom control that was developed by one of our users. I believe you can find it on the info-labwindows archive at http://welcome.to/cvi. If you are using CVI 6.0 you can also use Microsoft's TreeView ActiveX control.
There are detailed instructions in the help for the CVI User Interface Localizer. If you are using CVI 6.0, you can get to it by pressing the help button in the UI Localizer dialog.
Best Regards,
Chris Matthews
National Instruments