diff --git a/src/libslic3r/Fill/FillRectilinear.hpp b/src/libslic3r/Fill/FillRectilinear.hpp
index 0f372dbfd..9e3cc056e 100644
--- a/src/libslic3r/Fill/FillRectilinear.hpp
+++ b/src/libslic3r/Fill/FillRectilinear.hpp
@@ -8,7 +8,7 @@
 namespace Slic3r {
 
 class Surface;
-class SegmentedIntersectionLine;
+struct SegmentedIntersectionLine;
 struct ExPolygonWithOffset;
 
 class FillRectilinear : public Fill
diff --git a/src/slic3r/GUI/GUI_ObjectLayers.cpp b/src/slic3r/GUI/GUI_ObjectLayers.cpp
index 7d8643c7f..52fb297b6 100644
--- a/src/slic3r/GUI/GUI_ObjectLayers.cpp
+++ b/src/slic3r/GUI/GUI_ObjectLayers.cpp
@@ -291,7 +291,7 @@ void ObjectLayers::sys_color_changed()
             const std::vector<size_t> btns = {2, 3};  // del_btn, add_btn
             for (auto btn : btns) {
                 wxSizerItem* b_item = item->GetSizer()->GetItem(btn);
-                if (b_item->IsWindow()) {
+                if (b_item != nullptr && b_item->IsWindow()) {
                     auto button = dynamic_cast<PlusMinusButton*>(b_item->GetWindow());
                     if (button != nullptr)
                         button->msw_rescale();