diff --git a/include/igl/opengl/glfw/Viewer.cpp b/include/igl/opengl/glfw/Viewer.cpp
index 584bec1d9..e647f2ac3 100644
--- a/include/igl/opengl/glfw/Viewer.cpp
+++ b/include/igl/opengl/glfw/Viewer.cpp
@@ -1007,7 +1007,7 @@ namespace glfw
     }
     data_list[index].meshgl.free();
     data_list.erase(data_list.begin() + index);
-    if(selected_data_index >= index && selected_data_index>0)
+    if(selected_data_index >= index && selected_data_index > 0)
     {
       selected_data_index--;
     }
@@ -1027,13 +1027,13 @@ namespace glfw
   IGL_INLINE ViewerCore& Viewer::core(unsigned core_id /*= 0*/)
   {
     assert(!core_list.empty() && "core_list should never be empty");
-    int core_ind;
+    int core_index;
     if (core_id == 0)
-      core_ind = selected_core_index;
+      core_index = selected_core_index;
     else
-      core_ind = core_index(core_id);
-    assert((core_ind >= 0 && core_ind < core_list.size()) && "selected_core_index should be in bounds");
-    return core_list[core_ind];
+      core_index = this->core_index(core_id);
+    assert((core_index >= 0 && core_index < core_list.size()) && "selected_core_index should be in bounds");
+    return core_list[core_index];
   }
 
   IGL_INLINE bool Viewer::erase_core(const size_t index)
@@ -1042,14 +1042,14 @@ namespace glfw
     assert(data_list.size() >= 1);
     if (core_list.size() == 1)
     {
-      // Cannot remove last mesh
+      // Cannot remove last viewport
       return false;
     }
     core_list[index].shut(); // does nothing
     core_list.erase(core_list.begin() + index);
     if (selected_core_index >= index && selected_core_index > 0)
     {
-      selected_core_index>>=1;
+      selected_core_index--;
     }
     return true;
   }
@@ -1065,13 +1065,13 @@ namespace glfw
 
   IGL_INLINE int Viewer::append_core(Eigen::Vector4f viewport, bool append_empty /*= false*/)
   {
-    core_list.push_back(core()); //copies the previous core and only changes the viewport
+    core_list.push_back(core()); // copies the previous active core and only changes the viewport
     core_list.back().viewport = viewport;
     core_list.back().id = next_core_id;
     next_core_id <<= 1;
-    if(!append_empty)
+    if (!append_empty)
       for (auto &data : data_list)
-        data.set_visible(true,core_list.back().id);
+        data.set_visible(true, core_list.back().id);
     return core_list.back().id;
   }
 
diff --git a/tutorial/108_MultipleViews/main.cpp b/tutorial/108_MultipleViews/main.cpp
index dc24b7e5e..8be687cdc 100644
--- a/tutorial/108_MultipleViews/main.cpp
+++ b/tutorial/108_MultipleViews/main.cpp
@@ -11,7 +11,7 @@ int main(int argc, char * argv[])
 
   viewer.load_mesh_from_file(std::string(TUTORIAL_SHARED_PATH) + "/cube.obj");
   viewer.load_mesh_from_file(std::string(TUTORIAL_SHARED_PATH) + "/sphere.obj");
-  
+
   int left_view, right_view;
   int cube_id = viewer.data_list[0].id, sphere_id = viewer.data_list[1].id;
   viewer.callback_init = [&](igl::opengl::glfw::Viewer &)
@@ -26,10 +26,10 @@ int main(int argc, char * argv[])
   {
     if(key == GLFW_KEY_SPACE)
     {
-	  // by default, when a core is appended, all loaded meshes will be displayed in that core
-	  // displaying can be controlled by changing viewer.coreDataPairs
-	  viewer.data(cube_id).set_visible(false, left_view);
-	  viewer.data(sphere_id).set_visible(false, right_view);
+      // by default, when a core is appended, all loaded meshes will be displayed in that core
+      // displaying can be controlled by changing viewer.coreDataPairs
+      viewer.data(cube_id).set_visible(false, left_view);
+      viewer.data(sphere_id).set_visible(false, right_view);
     }
     return false;
   };