diff --git a/Graphics/drawMesh.cpp b/Graphics/drawMesh.cpp
index 824fe9557d5d53d8403b51de0817bec3f92be741..1240f3117024343a61d6782aa4d4b91833ca0369 100644
--- a/Graphics/drawMesh.cpp
+++ b/Graphics/drawMesh.cpp
@@ -702,6 +702,7 @@ void drawContext::drawMesh()
   for(unsigned int i = 0; i < GModel::list.size(); i++){
     GModel *m = GModel::list[i];
     bool changed = m->fillVertexArrays();
+    if(changed) Msg::Debug("mesh vertex arrays have changed");
 #if defined(HAVE_FLTK) && defined(__APPLE__)
     // FIXME: resetting texture pile fixes bug with recent MacOS versions
     if(changed) gl_texture_pile_height(gl_texture_pile_height());
diff --git a/Graphics/drawPost.cpp b/Graphics/drawPost.cpp
index a684ac3f20a47b4de286407ffa80865fce54659e..9c960352cceaca4f6ce003ad7903b5c2c7d2caaa 100644
--- a/Graphics/drawPost.cpp
+++ b/Graphics/drawPost.cpp
@@ -580,6 +580,7 @@ void drawContext::drawPost()
 
   for(unsigned int i = 0; i < PView::list.size(); i++){
     bool changed = PView::list[i]->fillVertexArrays();
+    if(changed) Msg::Debug("post-pro vertex arrays have changed");
 #if defined(HAVE_FLTK) && defined(__APPLE__)
     // FIXME: resetting texture pile fixes bug with recent MacOS versions
     if(changed) gl_texture_pile_height(gl_texture_pile_height());