diff --git a/Source/HtmlRenderer/HtmlRendererNET35.csproj b/Source/HtmlRenderer/HtmlRendererNET35.csproj
index 0c0288a1b..ab00bfdfe 100644
--- a/Source/HtmlRenderer/HtmlRendererNET35.csproj
+++ b/Source/HtmlRenderer/HtmlRendererNET35.csproj
@@ -68,6 +68,7 @@
     <Compile Include="Entities\HtmlScrollEventArgs.cs" />
     <Compile Include="Entities\HtmlStylesheetLoadEventArgs.cs" />
     <Compile Include="Entities\SubString.cs" />
+    <Compile Include="Entities\Tuple.cs" />
     <Compile Include="Handlers\BackgroundImageDrawHandler.cs" />
     <Compile Include="Handlers\BordersDrawHandler.cs" />
     <Compile Include="Handlers\ContextMenuHandler.cs" />
diff --git a/Source/HtmlRenderer/HtmlRendererNET40.csproj b/Source/HtmlRenderer/HtmlRendererNET40.csproj
index d95c8f503..a585da775 100644
--- a/Source/HtmlRenderer/HtmlRendererNET40.csproj
+++ b/Source/HtmlRenderer/HtmlRendererNET40.csproj
@@ -68,6 +68,7 @@
     <Compile Include="Entities\HtmlScrollEventArgs.cs" />
     <Compile Include="Entities\HtmlStylesheetLoadEventArgs.cs" />
     <Compile Include="Entities\SubString.cs" />
+    <Compile Include="Entities\Tuple.cs" />
     <Compile Include="Handlers\BackgroundImageDrawHandler.cs" />
     <Compile Include="Handlers\BordersDrawHandler.cs" />
     <Compile Include="Handlers\ContextMenuHandler.cs" />
diff --git a/Source/HtmlRenderer/HtmlRendererNET45.csproj b/Source/HtmlRenderer/HtmlRendererNET45.csproj
index 701390b60..501d5f83d 100644
--- a/Source/HtmlRenderer/HtmlRendererNET45.csproj
+++ b/Source/HtmlRenderer/HtmlRendererNET45.csproj
@@ -67,6 +67,7 @@
     <Compile Include="Entities\HtmlScrollEventArgs.cs" />
     <Compile Include="Entities\HtmlStylesheetLoadEventArgs.cs" />
     <Compile Include="Entities\SubString.cs" />
+    <Compile Include="Entities\Tuple.cs" />
     <Compile Include="Handlers\BackgroundImageDrawHandler.cs" />
     <Compile Include="Handlers\BordersDrawHandler.cs" />
     <Compile Include="Handlers\ContextMenuHandler.cs" />