diff --git a/libsrc/core/paje_trace.cpp b/libsrc/core/paje_trace.cpp
index f9c5ba89..773e1207 100644
--- a/libsrc/core/paje_trace.cpp
+++ b/libsrc/core/paje_trace.cpp
@@ -654,6 +654,10 @@ namespace ngcore
           }
           else
           {
+              if(node_stack.size()==0) {
+                std::cout << "node stack empty!" << std::endl;
+                break;
+              }
               double time = 1000.0*static_cast<double>(event.time-current->start_time)/ticks_per_second;
               current->time += time;
               current = node_stack.back();
diff --git a/libsrc/csg/CMakeLists.txt b/libsrc/csg/CMakeLists.txt
index 98475096..30d61a2d 100644
--- a/libsrc/csg/CMakeLists.txt
+++ b/libsrc/csg/CMakeLists.txt
@@ -11,7 +11,7 @@ if(APPLE)
     set_target_properties( csg PROPERTIES SUFFIX ".so")
 endif(APPLE)
 
-target_link_libraries(csg PUBLIC mesh ${PYTHON_LIBRARIES})
+target_link_libraries(csg PUBLIC mesh PRIVATE ${PYTHON_LIBRARIES})
 if(NOT WIN32)
   install( TARGETS csg ${NG_INSTALL_DIR})
 endif(NOT WIN32)
diff --git a/libsrc/geom2d/CMakeLists.txt b/libsrc/geom2d/CMakeLists.txt
index 395141e5..8809e06c 100644
--- a/libsrc/geom2d/CMakeLists.txt
+++ b/libsrc/geom2d/CMakeLists.txt
@@ -4,13 +4,11 @@ if(APPLE)
     set_target_properties( geom2d PROPERTIES SUFFIX ".so")
 endif(APPLE)
 
-target_link_libraries(geom2d mesh ${PYTHON_LIBRARIES})
+target_link_libraries(geom2d PUBLIC ngcore mesh PRIVATE ${PYTHON_LIBRARIES})
 if(NOT WIN32)
   install( TARGETS geom2d ${NG_INSTALL_DIR})
 endif(NOT WIN32)
 
-target_link_libraries(geom2d ngcore)
-
 if(USE_GUI)
     add_library(geom2dvis ${NG_LIB_TYPE} vsgeom2d.cpp)
     if(NOT WIN32)
diff --git a/libsrc/meshing/CMakeLists.txt b/libsrc/meshing/CMakeLists.txt
index f1e9ee86..23f302a7 100644
--- a/libsrc/meshing/CMakeLists.txt
+++ b/libsrc/meshing/CMakeLists.txt
@@ -23,7 +23,7 @@ endif(APPLE)
 
 target_link_libraries( mesh PUBLIC ngcore PRIVATE gprim la gen )
 
-target_link_libraries( mesh PUBLIC ${ZLIB_LIBRARIES} ${MPI_CXX_LIBRARIES} ${PYTHON_LIBRARIES} ${METIS_LIBRARY})
+target_link_libraries( mesh PRIVATE ${ZLIB_LIBRARIES} ${MPI_CXX_LIBRARIES} ${PYTHON_LIBRARIES} ${METIS_LIBRARY})
 if(NOT WIN32)
   install( TARGETS mesh ${NG_INSTALL_DIR})
 endif(NOT WIN32)
diff --git a/libsrc/occ/CMakeLists.txt b/libsrc/occ/CMakeLists.txt
index 1f093ad8..e4589b1b 100644
--- a/libsrc/occ/CMakeLists.txt
+++ b/libsrc/occ/CMakeLists.txt
@@ -11,7 +11,7 @@ endif(USE_GUI)
 target_link_libraries(occ PUBLIC ngcore)
 
 if(NOT WIN32)
-    target_link_libraries( occ PUBLIC ${OCC_LIBRARIES} ${PYTHON_LIBRARIES})
+    target_link_libraries( occ PRIVATE ${OCC_LIBRARIES} ${PYTHON_LIBRARIES})
     install( TARGETS occ ${NG_INSTALL_DIR})
     if (USE_GUI)
         target_link_libraries( occvis PUBLIC occ )
diff --git a/libsrc/stlgeom/CMakeLists.txt b/libsrc/stlgeom/CMakeLists.txt
index 8925c828..90d29b86 100644
--- a/libsrc/stlgeom/CMakeLists.txt
+++ b/libsrc/stlgeom/CMakeLists.txt
@@ -4,12 +4,11 @@ add_library(stl ${NG_LIB_TYPE}
         )
 
 if(NOT WIN32)
-    target_link_libraries( stl mesh ${PYTHON_LIBRARIES})
+    target_link_libraries( stl PUBLIC mesh PRIVATE ${PYTHON_LIBRARIES})
     install( TARGETS stl ${NG_INSTALL_DIR})
 endif(NOT WIN32)
 
-target_link_libraries( stl ngcore )
-
+target_link_libraries( stl PUBLIC ngcore )
 
 if(USE_GUI)
     add_library(stlvis ${NG_LIB_TYPE}
diff --git a/libsrc/visualization/CMakeLists.txt b/libsrc/visualization/CMakeLists.txt
index 4288862c..ddbbc03f 100644
--- a/libsrc/visualization/CMakeLists.txt
+++ b/libsrc/visualization/CMakeLists.txt
@@ -9,7 +9,7 @@ endif(USE_GUI)
 
 add_library(visual ${NG_LIB_TYPE} ${LIB_VISUAL_SOURCES})
 
-target_link_libraries( visual ngcore ${PYTHON_LIBRARIES} ${MPI_CXX_LIBRARIES} ${OPENGL_LIBRARIES} )
+target_link_libraries( visual PUBLIC ngcore PRIVATE ${PYTHON_LIBRARIES} ${MPI_CXX_LIBRARIES} ${OPENGL_LIBRARIES} )
 install( TARGETS visual ${NG_INSTALL_DIR})
 
 install(FILES
diff --git a/ng/CMakeLists.txt b/ng/CMakeLists.txt
index 45bee626..5e4e2c4e 100644
--- a/ng/CMakeLists.txt
+++ b/ng/CMakeLists.txt
@@ -30,7 +30,7 @@ if(USE_GUI)
       target_link_libraries( gui PRIVATE ${TCL_LIBRARY} ${TK_LIBRARY})
     endif(NOT APPLE)
 
-    target_link_libraries( netgen nglib gui ${LIBTOGL} ${ZLIB_LIBRARIES} ${JPEG_LIBRARIES} ${FFMPEG_LIBRARIES} ${X11_Xmu_LIB} ${X11_X11_LIB} ${OCC_LIBRARIES} ${TK_LIBRARY} ${TCL_LIBRARY} ${PYTHON_LIBRARIES})
+    target_link_libraries( netgen nglib gui ${MPI_mpi_LIBRARY} ${MPI_CXX_LIBRARIES} ${LIBTOGL} ${ZLIB_LIBRARIES} ${JPEG_LIBRARIES} ${FFMPEG_LIBRARIES} ${X11_Xmu_LIB} ${X11_X11_LIB} ${OCC_LIBRARIES} ${TK_LIBRARY} ${TCL_LIBRARY} ${PYTHON_LIBRARIES})
 
     if(NOT WIN32)
       target_link_libraries( netgen mesh stlvis stl geom2dvis interface geom2d csg stl visual csgvis )