Programmically changing label does not update UI

Hi,

I am setting the label propery of a button in a ribbon, eg:

<ribbon:Button
Label="xNew"
x:Name="btnNewIncident" />

In the code behind i then retrive the properties from a database and set in code:

btnNewIncident.Label = "New";

When stepping through the code, i can see the label's value changing, but the value change does not update the UI, even after a call to "Ribbon.InvalidateVisual();"

Can you assist?

Regards,

Craig