diff --git a/libsrc/core/CMakeLists.txt b/libsrc/core/CMakeLists.txt
index e18dd87d..7a8567c8 100644
--- a/libsrc/core/CMakeLists.txt
+++ b/libsrc/core/CMakeLists.txt
@@ -32,6 +32,7 @@ if(WIN32)
 endif(WIN32)
 
 target_compile_definitions(ngcore PUBLIC $<$<CONFIG:DEBUG>:NETGEN_ENABLE_CHECK_RANGE>)
+target_include_directories(ngcore INTERFACE $<INSTALL_INTERFACE:${NG_INSTALL_DIR_INCLUDE}> $<INSTALL_INTERFACE:${NG_INSTALL_DIR_INCLUDE}/include>)
 
 if(CHECK_RANGE)
   target_compile_definitions(ngcore PUBLIC NETGEN_ENABLE_CHECK_RANGE)
diff --git a/tests/pytest/compare_results.py b/tests/pytest/compare_results.py
index 8a74fb9d..82f578e6 100644
--- a/tests/pytest/compare_results.py
+++ b/tests/pytest/compare_results.py
@@ -82,7 +82,7 @@ for i,d in enumerate(['badness','#edges','#trigs','#tets']):
     ax = plt.subplot(2,5,6+i)
     plt.title('difference '+d+' (in %)')
 #     plt.violinplot([(y-x)/x for x,y in zip(data[d],data2[d])], showmedians=True)
-    plt.boxplot([(y-x)/x for x,y in zip(data[d],data2[d])])
+    plt.boxplot([100.0*(y-x)/x for x,y in zip(data[d],data2[d])])
     plt.hlines(0.0, 0.5,1.5, linestyle='dotted')