Hi,
This is a known problem with setting the string properties of some of the controls, the next version of MStudio will be fixed. In the mean time you can go to:
http://digital.ni.com/public.nsf/websearch/293E8E454599F54186256C2B00576943?OpenDocument
and download a fix for this problem. There is more info on this in the document.
I hope this helps,
Juan Carlos Contreras
National Instruments
Hola