diff --git a/src/misc_gui.cpp b/src/misc_gui.cpp
--- a/src/misc_gui.cpp
+++ b/src/misc_gui.cpp
@@ -330,6 +330,16 @@ public:
 	{
 		::ShowNewGRFInspectWindow(GetGrfSpecFeature(this->tile), this->tile);
 	}
+
+	virtual void OnInvalidateData(int data)
+	{
+		switch (data) {
+			case 1:
+				/* ReInit, "debug" sprite might have changed */
+				this->ReInit();
+				break;
+		}
+	}
 };
 
 /**
diff --git a/src/newgrf_debug_gui.cpp b/src/newgrf_debug_gui.cpp
--- a/src/newgrf_debug_gui.cpp
+++ b/src/newgrf_debug_gui.cpp
@@ -519,8 +519,7 @@ void DeleteNewGRFInspectWindow(GrfSpecFe
 	DeleteWindowById(WC_NEWGRF_INSPECT, wno);
 
 	/* Reinitialise the land information window to remove the "debug" sprite if needed. */
-	Window *w = FindWindowById(WC_LAND_INFO, 0);
-	if (w != NULL) w->ReInit();
+	InvalidateWindowData(WC_LAND_INFO, 0, 1);
 }
 
 /**