TextWrapping in a Textblock with binding

Hi! I have a problem with Textwrapping it not works

I put in my App:

<TextBlock Text="{Binding SelectedItem.OrdenSalida, ElementName=inventarioComboBox}" 
                        TextWrapping="Wrap" Width="80"/>   

where inventarioComboBox is binding with a sql db and OrdenSalida is a char(40) field, but if OrdenSalida = "1024, 2568, 4587" the view is truncated:

if I change my textblock:

<TextBlock Text= "1024, 2568, 4587" TextWrapping="Wrap" Width="80"/>    

it Works fine:

but when the textblock is binding it not Works, why???

I'm using  Silverlight  5.1.30514.0 with Windows 8

cyndyrdz