diff --git a/src/town_gui.cpp b/src/town_gui.cpp
--- a/src/town_gui.cpp
+++ b/src/town_gui.cpp
@@ -27,6 +27,7 @@
 #include "querystring_gui.h"
 #include "window_func.h"
 #include "townname_func.h"
+#include "core/backup_type.hpp"
 #include "core/geometry_func.hpp"
 #include "genworld.h"
 #include "stringfilter_type.h"
@@ -1184,15 +1185,16 @@ public:
 				this->SetFocusedWidget(WID_TF_TOWN_NAME_EDITBOX);
 				break;
 
-			case WID_TF_MANY_RANDOM_TOWNS:
-				_generating_world = true;
+			case WID_TF_MANY_RANDOM_TOWNS: {
+				Backup<bool> old_generating_world(_generating_world, true, FILE_LINE);
 				UpdateNearestTownForRoadTiles(true);
 				if (!GenerateTowns(this->town_layout)) {
 					ShowErrorMessage(STR_ERROR_CAN_T_GENERATE_TOWN, STR_ERROR_NO_SPACE_FOR_TOWN, WL_INFO);
 				}
 				UpdateNearestTownForRoadTiles(false);
-				_generating_world = false;
+				old_generating_world.Restore();
 				break;
+			}
 
 			case WID_TF_SIZE_SMALL: case WID_TF_SIZE_MEDIUM: case WID_TF_SIZE_LARGE: case WID_TF_SIZE_RANDOM:
 				this->town_size = (TownSize)(widget - WID_TF_SIZE_SMALL);