http://blogs.msdn.com/maximelamure/archive/2009/06/14/un-nouveau-correctif-pour-am-liorer-les-performances-d-affichage-du-designer-wpf-avec-visual-studio-2008-sp1-a-new-fix-to-improve-display-performance-of-the-wpf-deginer-from-visual-studio-2008-sp1.aspx[English] During your WPF development with Visual Studio 2008 SP1, you may encounter the following error: the IDE stops responding and you receive a message in the notification area: "Microsoft Visual Studio is Busy". In this case, know that a Fix hasen-USCommunityServer 2.1 SP1 (Build: 61025.2)