Getting a 'Prefix 'Controls' does not map to a namespace' error

[AnotherKiwi]

I'm getting an error when base.OnInitialized(e); in the MultiSelectTreeViewItem.OnInitialized() method executes:

MS.Internal.Xaml.Parser.GenericTypeNameParser.TypeNameParserException occurred HResult=0x80131500 Message=Prefix 'Controls' does not map to a namespace. Source=System.Xaml StackTrace: at MS.Internal.Xaml.Parser.GenericTypeNameParser.Callout_FoundName(String prefix, String name)

I thought this might be related to MultiSelectTreeView using the System.Windows.Controls namespace, so I tried changing its namespace to UnclassifiedSoftware.Controls. After that change the demo app again runs without error, but I still get the Prefix 'Controls' does not map to a namespace when I run my application. Any suggestions to overcome this?

[perkasthor]

I've solved this issue by updating the source code according to this answer: #41 (comment)