diff --git a/src/fluency/ui/main_window.py b/src/fluency/ui/main_window.py
index 17d76c8..bd969b0 100644
--- a/src/fluency/ui/main_window.py
+++ b/src/fluency/ui/main_window.py
@@ -3366,11 +3366,17 @@ class MainWindow(QMainWindow):
             self._current_component = None
             self._current_sketch = None
             self._selected_body = None
+            self._selected_assembly_component_id = None
+            self._assembly_view_active = False
 
             for btn in self._component_buttons:
                 btn.deleteLater()
             self._component_buttons.clear()
 
+            for btn in self._assembly_component_buttons:
+                btn.deleteLater()
+            self._assembly_component_buttons.clear()
+
             # set_sketch(None) clears the underlay entities via the new
             # set_sketch guard, but we also need to drop the saved source face
             # and reset the workplane buttons to their disabled state.