Visual Studio Silverlight XAML designer very slow - solution to problem

The XAML designer in Visual Studio 2010 is very slow, now extremely slow.  Sometime you have to wait minutes.   If you add RIA, MVVM and Prism into the mix it become unusable.  And then you may end up editing plain xaml code.

I seen a blog somewhere where they blame the Ria services.  Well, yes, I found the problem to be  Microsoft.ServiceModel.DomainServices.WindowsAzure.dll assembly.

I deleted the file and since then the designer runs smoothly.  The file can be found in the C:\Program Files (x86)\Microsoft SDKs\RIA Services\v1.0\Toolkit\Libraries\Server folder

Since then it is a pleasure to work with the designer..
Within seconds of opening a view the designer displays my xaml views.

Funny enough - this also solved my problem of duplicate entries in the Visual Studio Toolbox,  I think the toolbox creator crash when it tries to find toolbox items in the Azure assembly and then recreates some items in the toolbox.  Since I removed this assembly my Toolbox is not duplicating items anymore.