diff --git a/build/atlex.props b/build/atlex.props
index ba068ee..ac5d6e8 100644
--- a/build/atlex.props
+++ b/build/atlex.props
@@ -8,7 +8,7 @@
   </PropertyGroup>
   <ItemDefinitionGroup>
     <ClCompile>
-      <AdditionalIncludeDirectories>..\include\atlex</AdditionalIncludeDirectories>
+      <AdditionalIncludeDirectories>..\include\atlex;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <PrecompiledHeader>Use</PrecompiledHeader>
       <PrecompiledHeaderFile>stdafx.h</PrecompiledHeaderFile>
     </ClCompile>