diff --git a/src/slic3r/GUI/GUI_App.cpp b/src/slic3r/GUI/GUI_App.cpp
index b2282a5ee..c1ef3e10d 100644
--- a/src/slic3r/GUI/GUI_App.cpp
+++ b/src/slic3r/GUI/GUI_App.cpp
@@ -747,7 +747,7 @@ void GUI_App::load_current_presets()
 void GUI_App::MacOpenFiles(const wxArrayString &fileNames)
 {
     std::vector<std::string> files;
-    for (size_t i = 0; i < fileNames.Len(); ++ i)
+    for (size_t i = 0; i < fileNames.GetCount(); ++ i)
         files.emplace_back(fileNames[i].ToUTF8().data());
     this->plater()->load_files(files, true, true);
 }
diff --git a/src/slic3r/GUI/wxExtensions.hpp b/src/slic3r/GUI/wxExtensions.hpp
index b6f7a4220..18e7155be 100644
--- a/src/slic3r/GUI/wxExtensions.hpp
+++ b/src/slic3r/GUI/wxExtensions.hpp
@@ -329,7 +329,7 @@ public:
 	{
 		if (GetChildCount() == 0)
 			return;
-		for (size_t id = GetChildCount() - 1; id >= 0; --id)
+		for (int id = int(GetChildCount()) - 1; id >= 0; --id)
 		{
 			if (m_children.Item(id)->GetChildCount() > 0)
 				m_children[id]->RemoveAllChildren();