I've created a resource dictionary RadRibbon and copied/pasted the resources from the NET40 implicit style resource dictionary.  Visual studio 2012 renders & builds fine, but Blend crashes whenever I open the project.  When I debug blend with vs 2012, it reports:

'{DependencyProperty.UnsetValue}' is not a valid value for the 'Telerik.Windows.Controls.RadRibbonGallery.Icon' property on a Setter.

Please advise.

Hi Sheldon,

We fixed that issue during this release cycle and you could download the latest binaries in a few days.

However, if you do not want to wait for the new release, you can workaround the issue. It is caused by the currently defined Icon property Setter:
it has to be defined like this instead:

I hope this information helps.

Kind regards,
Kiril Vandov
the Telerik team