diff --git a/src/genworld_gui.cpp b/src/genworld_gui.cpp
--- a/src/genworld_gui.cpp
+++ b/src/genworld_gui.cpp
@@ -587,13 +587,21 @@ struct GenerateLandscapeWindow : public 
 				}
 				break;
 
-			case GLAND_TERRAIN_PULLDOWN:
+			case GLAND_TERRAIN_PULLDOWN: {
+				byte old_gm = _game_mode;
+				_game_mode = GM_MENU;
 				IConsoleSetSetting("difficulty.terrain_type", index);
+				_game_mode = old_gm;
 				break;
+			}
 
-			case GLAND_WATER_PULLDOWN:
+			case GLAND_WATER_PULLDOWN: {
+				byte old_gm = _game_mode;
+				_game_mode = GM_MENU;
 				IConsoleSetSetting("difficulty.quantity_sea_lakes", index);
+				_game_mode = old_gm;
 				break;
+			}
 		}
 		this->SetDirty();
 	}