Fixed of the warnings.

+ Some small bug-fixing related to the system colors change on MacOS ("Set..." buttons didn't respect to the system color change)

src/slic3r/GUI/OptionsGroup.cpp

@@ -747,6 +747,10 @@ void ConfigOptionsGroup::sys_color_changed()
             wxGetApp().UpdateDarkUI(extra_col);
     }
 
+    if (custom_ctrl)
+        wxGetApp().UpdateDarkUI(custom_ctrl);
+#endif
+
     auto update = [](wxSizer* sizer) {
         for (wxSizerItem* item : sizer->GetChildren())
             if (item->IsWindow()) {
@@ -768,10 +772,6 @@ void ConfigOptionsGroup::sys_color_changed()
             update(line.extra_widget_sizer);
     }
 
-    if (custom_ctrl)
-        wxGetApp().UpdateDarkUI(custom_ctrl);
-#endif
-
 	// update undo buttons : rescale bitmaps
 	for (const auto& field : m_fields)
 		field.second->sys_color_changed();