diff --git a/src/libslic3r/Technologies.hpp b/src/libslic3r/Technologies.hpp
index 480ca0ee5..386728efb 100644
--- a/src/libslic3r/Technologies.hpp
+++ b/src/libslic3r/Technologies.hpp
@@ -49,7 +49,7 @@
 #define ENABLE_RELOAD_FROM_DISK_FOR_3MF (1 && ENABLE_2_4_0_ALPHA0)
 // Removes obsolete warning texture code
 #define ENABLE_WARNING_TEXTURE_REMOVAL (1 && ENABLE_2_4_0_ALPHA0)
-// Enable showing gcode line numbers in previeww horizontal slider
+// Enable showing gcode line numbers in preview horizontal slider
 #define ENABLE_GCODE_LINES_ID_IN_H_SLIDER (1 && ENABLE_2_4_0_ALPHA0)
 // Enable validation of custom gcode against gcode processor reserved keywords
 #define ENABLE_VALIDATE_CUSTOM_GCODE (1 && ENABLE_2_4_0_ALPHA0)
diff --git a/src/slic3r/GUI/ProjectDirtyStateManager.cpp b/src/slic3r/GUI/ProjectDirtyStateManager.cpp
index d538b0cf7..9ff4821c2 100644
--- a/src/slic3r/GUI/ProjectDirtyStateManager.cpp
+++ b/src/slic3r/GUI/ProjectDirtyStateManager.cpp
@@ -180,6 +180,9 @@ void ProjectDirtyStateManager::update_from_undo_redo_stack(UpdateType type)
         return;
 
     const Plater* plater = wxGetApp().plater();
+    if (plater == nullptr)
+        return;
+
     const UndoRedo::Stack& main_stack = plater->undo_redo_stack_main();
     const UndoRedo::Stack& active_stack = plater->undo_redo_stack_active();