--- a/src/newgrf_gui.cpp	Mon Feb 26 22:32:21 2007 +0000
+++ b/src/newgrf_gui.cpp	Tue Feb 27 15:17:06 2007 +0000
@@ -485,6 +485,9 @@
 			break;
 
 		case WE_DESTROY:
+			if (!WP(w, newgrf_d).execute) {
+				CopyGRFConfigList(WP(w, newgrf_d).orig_list, *WP(w, newgrf_d).list);
+			}
 			/* Remove the temporary copy of grf-list used in window */
 			ClearGRFConfigList(WP(w, newgrf_d).list);
 			break;