diff --git a/samples/XamlDesigner/XamlDesigner.csproj b/samples/XamlDesigner/XamlDesigner.csproj
index bb9af8668d..a39fb21053 100644
--- a/samples/XamlDesigner/XamlDesigner.csproj
+++ b/samples/XamlDesigner/XamlDesigner.csproj
@@ -49,6 +49,9 @@
       <SpecificVersion>False</SpecificVersion>
       <HintPath>Libraries\AvalonDock.dll</HintPath>
     </Reference>
+    <Reference Include="ICSharpCode.SharpDevelop.Widgets">
+      <HintPath>..\..\bin\ICSharpCode.SharpDevelop.Widgets.dll</HintPath>
+    </Reference>
     <Reference Include="ICSharpCode.TextEditor, Version=3.0.0.3267, Culture=neutral, PublicKeyToken=4d61825e8dd49f1a, processorArchitecture=MSIL">
       <SpecificVersion>False</SpecificVersion>
       <HintPath>..\..\bin\ICSharpCode.TextEditor.dll</HintPath>