Fix: The tag XXX does not exist in XML namespace ‘clr-namespace:YYY’

Fix: The tag XXX does not exist in XML namespace ‘clr-namespace:YYY’https://www.dotnetzone.gr:443/cs/blogs/birbilis/archive/2012/07/02/fix-the-tag-xxx-does-not-exist-in-xml-namespace-clr-namespace-yyy.aspxI just had some big trouble troubleshooting the Visual Studio / XAML compiler error message: The tag XXX does not exist in XML namespace ‘clr-namespace:YYY’ It turned out this occurred because I had a Silverlight library with Assembly nameelCommunityServer 2.1 SP3 (Build: 20423.1)