Hi Ronny
The solution is to make the vi you want to call a vi template ie a vit. When you call a vit labVIEW creates a unique instance of it and hence it will have its own user interface, unlike a reentrant vi.
Take a look at the attached demo, it allows you to display multiple instances of MenuSelect.vit, in each instance you can make a menu selection.
Hope this helps
Kurt Friday
www.sciware.com.au