Jusy Copy
AndroidDesigner.jar
from
"C:\Program Files (x86)\Xamarin Studio\AddIns\MonoDevelop.MonoDroid\java\AndroidDesigner.jar"
to
"C:\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE\Extensions\Xamarin\Xamarin.Android\4.7.04014\java\AndroidDesigner.jar"
This works well for me :) ;)
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