diff --git a/samples/BindingTest/BindingTest.csproj b/samples/BindingTest/BindingTest.csproj
index 441802e396..1996ed71d4 100644
--- a/samples/BindingTest/BindingTest.csproj
+++ b/samples/BindingTest/BindingTest.csproj
@@ -161,6 +161,14 @@
       <Project>{811a76cf-1cf6-440f-963b-bbe31bd72a82}</Project>
       <Name>Avalonia.Win32</Name>
     </ProjectReference>
+    <ProjectReference Include="..\..\src\Gtk\Avalonia.Gtk\Avalonia.Gtk.csproj">
+      <Project>{54F237D5-A70A-4752-9656-0C70B1A7B047}</Project>
+      <Name>Avalonia.Gtk</Name>
+    </ProjectReference>
+    <ProjectReference Include="..\..\src\Gtk\Avalonia.Cairo\Avalonia.Cairo.csproj">
+      <Project>{FB05AC90-89BA-4F2F-A924-F37875FB547C}</Project>
+      <Name>Avalonia.Cairo</Name>
+    </ProjectReference>
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
diff --git a/samples/VirtualizationTest/VirtualizationTest.csproj b/samples/VirtualizationTest/VirtualizationTest.csproj
index 1852950992..e6a72e97c7 100644
--- a/samples/VirtualizationTest/VirtualizationTest.csproj
+++ b/samples/VirtualizationTest/VirtualizationTest.csproj
@@ -150,6 +150,14 @@
       <Project>{811a76cf-1cf6-440f-963b-bbe31bd72a82}</Project>
       <Name>Avalonia.Win32</Name>
     </ProjectReference>
+    <ProjectReference Include="..\..\src\Gtk\Avalonia.Cairo\Avalonia.Cairo.csproj">
+      <Project>{FB05AC90-89BA-4F2F-A924-F37875FB547C}</Project>
+      <Name>Avalonia.Cairo</Name>
+    </ProjectReference>
+    <ProjectReference Include="..\..\src\Gtk\Avalonia.Gtk\Avalonia.Gtk.csproj">
+      <Project>{54F237D5-A70A-4752-9656-0C70B1A7B047}</Project>
+      <Name>Avalonia.Gtk</Name>
+    </ProjectReference>
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="App.xaml">