diff --git a/client/citydlg.cpp b/client/citydlg.cpp
index cdf9fc8f9b..2d77dfa5fc 100644
--- a/client/citydlg.cpp
+++ b/client/citydlg.cpp
@@ -1472,6 +1472,7 @@ void city_dialog::hideEvent(QHideEvent *event)
       unit_focus_update();
     }
     update_map_canvas_visible();
+    pcity = nullptr;
   }
   queen()->mapview_wdg->show_all_fcwidgets();
 }
diff --git a/client/citydlg.h b/client/citydlg.h
index f602c7479b..488dd262c8 100644
--- a/client/citydlg.h
+++ b/client/citydlg.h
@@ -359,7 +359,7 @@ class city_dialog : public QWidget {
   void setup_ui(struct city *qcity);
   void refresh();
   void cma_check_agent();
-  struct city *pcity;
+  struct city *pcity = nullptr;
   bool dont_focus{false};
 
 private: