diff --git a/shadowsocks-csharp/shadowsocks-csharp.csproj b/shadowsocks-csharp/shadowsocks-csharp.csproj
index fe4b7b1f..278b0b47 100755
--- a/shadowsocks-csharp/shadowsocks-csharp.csproj
+++ b/shadowsocks-csharp/shadowsocks-csharp.csproj
@@ -61,7 +61,7 @@
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Data" />
-    <Reference Include="System.Drawing" />
+    <Reference Include="System.Drawing" />
     <Reference Include="System.Windows.Forms" />
     <Reference Include="System.XML" />
   </ItemGroup>